Polyethylene for Injection Moldings

ABSTRACT

Polyethylene which comprises ethylene homopolymers and/or copolymers of ethylene with 1-alkenes and has a molar mass distribution width M w /M n  of from 3 to 30, a density of from 0.945 to 0.965 g/cm 3 , a weight average molar mass M w  of from 50 000 g/mol to 200 000 g/mol, a HLMI of from 10 to 300 g/10 min and has from 0.1 to 15 branches/1000 carbon atoms, wherein the 1 to 15 % by weight of the polyethylene having the highest molar masses have a degree of branching of more than 1 branch of side chains larger than CH 3 /1000 carbon atoms, a process for its preparation, catalysts suitable for its preparation and also injection moldings in which this polyethylene is present

This application is the U.S. national phase of International Application PCT/EP2005/004412, filed Apr. 25, 2005, claiming priority to German Patent Application 102004020524.8 filed Apr. 26, 2004, and the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 60/587,533, filed Jul. 13, 2004; the disclosures of International Application PCT/EP2005/004412, German Patent Application 102004020524.8 and U.S. Provisional Application No. 60/587,533, each as filed, are incorporated herein by reference.

DESCRIPTION

The present invention relates to a novel polyethylene, which comprises ethylene homopolymers and/or copolymers of ethylene with 1-alkenes and has a molar mass distribution width M_(w)/M_(n) of from 3 to 30, a density of from 0.945 to 0.965 g/cm³, a weight average molar mass M_(w) of from 50 000 g/mol to 200 000 g/mol, a HLMI of from 10 to 300 g/10 min and has from 0.1 to 15 branches/1000 carbon atoms, wherein the 1 to 15% by weight of the polyethylene having the highest molar masses have a degree of branching of more than 1 branch of side chains larger than CH₃/1000 carbon atoms, a catalyst composition and a process for its preparation, and also injection moldings in which this polyethylene is present.

Blends of different polyethylenes are known and used for the preparation of injection moldings with a high stress crack resistance as disclosed in DE-C 34 37 116.

In recent times, polyethylene blends have been used in injection molding to produce many types of screw closures. It is advantageous if the screw closures retain their dimension and shape during cooling after the injection molding procedure, i.e. do not shrink (low shrinkage). Low shrinkage coupled with retention of shape represent an important property of plastics, which are to be used for example to produce screw closures with accurate fit. Furthermore the injection molding process is usually easier to perform if the polyethylene molding compositions have good flowability in the melt. Ever higher demands are made of the mechanical strength of moldings comprising polyethylene. On the other hand godd processability achieving high through-puts are required.

WO 00/71615 discloses injection molded containers from bimodal polyethylene, having a density of from 0.950 to 0.98 g/cm³, a crystallinity of from 60 to 90%, consisting of at least 2 polyethylene components with different molar mass distribution and wherein at least one component is a copolymer of ethylene. The polyethylene is obtained via a reactor cascade or by melt extrusion of the two components.

The known ethylene copolymer blends still leave something to be desired in terms of the combination of good mechanical properties, high flowability of the melt and good optical properties.

It has surprisingly been found that this object can be achieved using a specific catalyst composition by means of which a polyethylene having good mechanical properties, good processability and good optical properties can be prepared.

We have accordingly found a polyethylene which comprises ethylene homopolymers and/or copolymers of ethylene with 1-alkenes and has a molar mass distribution width M_(w)/M_(n) of from 3 to 30, a density of from 0.945 to 0.965 g/cm³, a weight average molar mass M_(w) of from 50 000 g/mol to 200 000 g/mol, a HLMI of from 10 to 300 g/10 min and has from 0.1 to 15 branches/1000 carbon atoms, wherein the 1 to 15% by weight of the polyethylene having the highest molar masses have a degree of branching of more than 1 branch of side chains larger than CH₃/1000 carbon atoms.

We have also found injection moldings, caps and closures in which the polyethylene of the invention is present as a significant component. Furthermore, we have found the use of the polyethylenes of the invention for producing injection moldings.

We have also found a catalyst system for preparing the polyethylenes of the invention, the use of the catalyst system for the polymerization of ethylene and/or copolymerization of ethylene with 1-alkenes and a process for preparing the polyethylene of the invention by polymerization of ethylene and/or copolymerization of ethylene with 1-alkenes in the presence of the catalyst system.

The polyethylene of the invention has a molar mass distribution width M_(w)/M_(n) in the range from 3 to 30, preferably from 5 to 20 and particularly preferably from 6 to 15. The density of the polyethylene of the invention is in the range from 0.945 to 0.965 g/cm³, preferably from 0.947 to 0.96 g/cm³ and particularly preferably in the range from 0.948 to 0.955 g/cm³. The weight average molar mass M_(w) of the polyethylene of the invention is in the range from 50 000 g/mol to 200 000 g/mol, preferably from 70 000 g/mol to 150 000 g/mol and particularly preferably from 80 000 g/mol to 120 000 g/mol. The HLMI of the polyethylene of the invention is in the range from 10 to 300 g/10 min, preferably from 50 to 200 g/10 min and particularly preferably in the range from 70 to 150 g/10 min. For the purposes of this invention, the expression “HLMI” refers as known to the “high load melt index” and is determined at 190° C. under a load of 21.6 kg (190° C./21.6 kg) in accordance with ISO 1133.

The density [g/cm³] was determined according to ISO 1183. The determination of the molar mass distributions and the means Mn, Mw, and Mw/Mn derived therefrom was carried out by means of high-temperature gel permeation chromatography on a WATERS 150 C using a method based on DIN 55672 and the following columns connected in series: 3× SHODEX AT 806 MS, 1× SHODEX UT 807 and 1× SHODEX AT-G under the following conditions: solvent: 1,2,4-trichlorobenzene (stabilized with 0.025% by weight of 2,6-di-tert-butyl-4-methylphenol), flow: 1 ml/min, 500 μl injection volume, temperature: 135° C., calibration using PE Standards. Evaluation was carried out using WIN-GPC.

The polyethylene of the invention has from 0.1 to 15 branches/1000 carbon atoms, preferably from 0.2 to 8 branches/1000 carbon atoms and particularly preferably from 0.3 to 3 branches/1000 carbon atoms. The branches/1000 carbon atoms are determined by means of ¹³C-NMR, as described by James. C. Randall, JMS-REV. Macromol. Chem. Phys., C29 (2&3), 201-317 (1989), and refer to the total content of CH₃ groups/1000 carbon atoms.

Furthermore, the polyethylene of the invention has 1 to 15% by weight of the polyethylene having the highest molar masses, preferably 2 to 12% by weight and particularly preferable 3 to 8% by weight have a degree of branching of more than 1 branch of side chains larger than CH₃/1000 carbon atoms, preferably in the range from 2 to 20 branches of side chains larger than CH₃/1000 carbon atoms and particularly preferably in the range from 5 to 15 branches of side chains larger than CH₃/1000 carbon atoms. This can be determined by solvent-nonsolvent fractionation, later called Holtrup fractionation as described in W. Holtrup, Makromol. Chem. 178, 2335 (1977) coupled with IR measurement of the different fractions. Xylene and ethylene glycol diethyl ether at 130° C. were used as solvents for the fractionation. 5 g of polyethylene were used and were divided into 8 fractions. The fractions are subsequently examined by ¹³C-NMR spectroscopy. The degree of branching in the various polymer fractions can be determined by means of ¹³C-NMR as described by James. C. Randall, JMS-REV. Macromol. Chem. Phys., C29 (2&3), 201-317 (1989). The polyethylene of the invention preferably has a CDBI of less than 50%, in particular from 10 to 45%. The method of determining the CDBI is described, for example in WO 93/03093. The TREF method is described, for example, in Wild, Advances in Polymer Science, 98, p. 1-47, 57 p. 153, 1992. The CDBI is defined as the percentage by weight of the copolymer molecules having a comonomer content of ±25% of the mean total molar comonomer content. Branches of side chains larger than CH₃ refers to the content of side chains/1000 carbon atoms without the end groups.

The molar mass distribution of the polyethylene of the invention can be monomodal, bimodal or multimodal. In the present patent application, a monomodal molar mass distribution means that the molar mass distribution has a single maximum. A bimodal molar mass distribution means, for the purposes of the present patent application, that the molar mass distribution has at least two points of inflection on one flank starting from a maximum. The molar mass distribution is preferably monomodal or bimodal, in particular bimodal.

The 1 to 15% by weight of the polyethylene of the invention having the highest molar masses, preferably the 2 to 12% by weight and particularly preferable 3 to 8% by weight when fractionated by gel permeation chromatography (GPC), and then this fraction is examined by “analytical temperature rising elution fractionation technique” (TREF), preferably do not show a high density polyethylene peak with a maximum above 80° C., preferably above 85° C. and particularly preferable above 90° C. The concentration of polymer in the fractions obtained at various temperatures is measured by means of infrared spectroscopy. The TREF result can also be calibrated by means of preparatively isolated polyethylene fractions having a defined number of short chain branches. The TREF method is described, for example, in Wild, Advances in Polymer Science, 98, p. 1-47, 57 p. 153, 1992.

When the polyethylene of the invention is examined by TREF, the fractions at a maximum above 80° C., preferably above 85° C. and particularly preferable above 90° C., when examined by GPC preferably show only polyethylene with molar masses below 1 Mio g/mol as opposed to polyethylenes obtained with the usual Ziegler catalysts.

The polyethylene of the invention preferably has a degree of long chain branching λ (lambda) of from 0 to 2 long chain branches/10 000 carbon atoms and particularly preferably from 0.1 to 1.5 long chain branches/10 000 carbon atoms. The degree of long chain branching λ (lambda) was measured by light scattering as described, for example, in ACS Series 521, 1993, Chromatography of Polymers, Ed. Theodore Provder; Simon Pang and Alfred Rudin: Size-Exclusion Chromatographic Assessment of Long-Chain Branch Frequency in Polyethylenes, page 254-269.

Preferably the 5-50% by weight of the polyethylene of the invention having the lowest molar masses, preferably 10-40% by weight and particularly preferably 15-30% by weight, have a degree of branching of less than 10 branches/1000 carbon atoms. This degree of branching in the part of the polyethylene having the lowest molar masses is preferably from 0.01 to 9 branches/1000 carbon atoms and particularly preferably from 0.1 to 6 branches/1000 carbon atoms. This can be determined by means of the Holtrup/¹³C-NMR method described. The branches/1000 carbon atoms are determined by means of ¹³C-NMR, as described by James. C. Randall, JMS-REV. Macromol. Chem. Phys., C29 (2&3), 201-317 (1989), and refer to the total content of CH₃ groups/1000 carbon atoms

The polyethylene of the invention has at least 0.2 vinyl groups/1000 carbon atoms, preferably from 0.7 to 5 vinyl groups/1000 carbon atoms and particularly preferably from 0.9 to 3 vinyl groups/1000 carbon atoms. The content of vinyl groups/1000 carbon atoms is determined by means of IR, ASTM D 6248-98. For the present purposes, the expression vinyl groups refers to —CH═CH₂ groups; vinylidene groups and internal olefinic groups are not encompassed by this expression. Vinyl groups are usually attributed to a polymer termination reaction after an ethylene insertion, while vinylidene end groups are usually formed after a poymer termination reaction after a comonomer insertion.

The polyethylene of the invention preferably has from 0.01 to 20 branches of side chains larger than CH₃/1000 carbon atoms, preferably side chains from C₂-C₆/1000 carbon atoms, preferably from 1 to 15 branches of side chains larger than CH₃/1000 carbon atoms, preferably side chains from C₂-C₆/1000 carbon atoms and particularly preferably from 2 to 8 branches of side chains larger than CH₃/1000 carbon atoms, preferably side chains from C₂-C₆/1000 carbon atoms. The branches of side chains larger than CH₃/1000 carbon atoms are determined by means of ¹³C-NMR, as determined by James. C. Randall, JMS-REV. Macromol. Chem. Phys., C29 (2&3), 201-317 (1989), and refer to the total content of side chains larger than CH₃ groups/1000 carbon atoms (without end groups). It is particularly preferred in polyethylene with 1-butene, 1-hexene or 1-octene as the α-olefin to have 0.01 to 20 ethyl, butyl or hexyl side branches/1000 carbon atoms, preferably from 1 to 15 ethyl, butyl or hexyl side branches/1000 carbon atoms and particularly preferably from 2 to 8 ethyl, butyl or hexyl side branches/1000 carbon atoms. This refers to the content of ethyl, butyl or hexyl side chains/1000 carbon atoms without the end groups.

In the polyethylene of the invention, the part of the polyethylene having a molar mass of less than 10 000 g/mol, preferably less than 20 000, preferably has a degree of branching of from 0 to 1.5 branches of side chains larger than CH₃/1000 carbon atoms, preferably side chains from C₂-C₆/1000 carbon atoms. Particular preference is given to the part of the polyethylene having a molar mass of less than 10 000 g/mol, preferably less than 20 000, having a degree of branching of from 0.1 to 0.9 branches of side chains larger than CH₃/1000 carbon atoms, preferably side chains from C₂-C₆/1000 carbon atoms. Preferably the polyethylene of the invention with 1-butene, 1-hexene or 1-octene as the 1-alkene, the part of the polyethylene having a molar mass of less than 10 000 g/mol, preferably less than 20 000, preferably has a degree of from 0 to 1.5 ethyl, butyl or hexyl branches of side chains/1000 carbon atoms. Particular preference is given to the part of the polyethylene having a molar mass of less than 10 000 g/mol, preferably less than 20 000, having a degree of branching of from 0.1 to 0.9 ethyl, butyl or hexyl branches of side chains/1000 carbon atoms. This too, can be determined by means of the Holtrup/¹³C-NMR method described.

Furthermore, it is preferred that at least 70% of the branches of side chains larger than CH₃ in the polyethylene of the invention are present in the 50% by weight of the polyethylene having the highest molar masses. This too can be determined by means of the Holtrup/¹³C-NMR method described.

The polyethylene of the invention preferably has a mixing quality measured in accordance with ISO 13949 of less than 3, in particular from 0 to 2.5. This value is based on the polyethylene taken directly from the reactor, i.e. the polyethylene powder without prior melting in an extruder. This polyethylene powder is preferably obtainable by polymerization in a single reactor.

As 1-alkenes, which are the comonomers which can be present in the ethylene copolymers, either individually or in a mixture with one another, in addition to ethylene in the ethylene copolymer part of the polyethylene of the invention, it is possible to use all 1-alkenes having from 3 to 12 carbon atoms, e.g. propene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and 1-decene. The ethylene copolymer preferably comprises 1-alkenes having from 4 to 8 carbon atoms, e.g. 1-butene, 1-pentene, 1-hexene, 4-methylpentene or 1-octene, in copolymerized form as comonomer unit. Particular preference is given to using 1-alkenes selected from the group consisting of 1-butene, 1-hexene and 1-octene. The polyethylene of the invention comprises preferentially 0.01 to 5% by weight, preferably 0.1 to 3 by weight of comonomer.

The polyethylene of the invention can further comprise of from 0 to 6% by weight, preferably 0.1 to 1 by weight of auxiliaries and/or additives known per se, e.g. processing stabilizers, stabilizers against the effects of light and heat, customary additives such as lubricants, antioxidants, antiblocking agents and antistatics, and also, if appropriate, dyes. A person skilled in the art will be familiar with the type and amount of these additives.

Furthermore, it has been found that the processing properties of the polyethylenes of the invention can be improved further by incorporation of small amounts of fluoroelastomers or thermoplastic polyesters. Such fluoroelastomers are known as such as processing aids and are commercially available, for example, under the trade names Viton® and Dynamar® (cf. also, for example, U.S. Pat. No. 3,125,547). They are preferably added in amounts of from 10 to 1000 ppm, particularly preferably from 20 to 200 ppm, based on the total mass of the polymer blend according to the invention.

In general mixing of the additives and the polyethylene of the invention can be carried out by all known methods. It can be done, for example, by introducing the powder components into a granulation apparatus, e.g. a twin-screw kneader (ZSK), Farrel kneader or Kobe kneader. The granulated mixture can also be processed directly on a film production plant.

We have also found the use of the polyethylenes of the invention for producing injection moldings, and injection moldings, preferably screw closures, caps, tube shoulders and engineering parts in which the polyethylene of the invention is present as a significant component.

Injection moldings, screw closures and caps, tube shoulders and engineering parts in which the polyethylene of the invention is present as a significant component are ones which contain from 50 to 100% by weight, preferably from 60 to 90% by weight, of the polyethylene of the invention, based on the total polymer material used for manufacture. In particular, injection moldings, screw closures and caps in which one of the layers contains from 50 to 100% by weight of the polyethylene of the invention are also included.

The polyethylene and the injection moldings of the invention with a thickness of 1 mm have preferably a haze, as determined according to ASTM D 1003-00 on a BYK Gardener Haze Guard Plus Device on at least 5 pieces of film 10×10 cm below 94%, preferably of from 10 to 92% and particularly preferably of from 50 to 91%. The stress crack resistance (full notch creep test (FNCT)) of the polyethylene and injection moldings as determined according to ISO DIS2 16770 at a pressure of 3.5 Mbar at 80° C. in a 2% by weight solution of Akropal N(N=10) in water, is preferably at least 5 h, preferably of from 6 to 80 h and particularly preferably of from 7 to 20 h. The polyethylene and the injection moldings of the invention with a thickness of 1 mm have preferably an impact resistance as determined according to the instrument falling weight impact test according to ISO 6603 at −20° C. of at least 12 J.

The polyethylene can be processed on conventional injection molding machines. The finish on the moldings obtained is homogeneous and can be improved further by increasing the rate of injection or raising the mould temperature.

The flow properties under process conditions were determined with the spiral flow test. The polyethylene is injected at a defined temperature, pressure and screw speed into a spiral mould to obtain coils with various wall thicknesses. The length of the coil obtained can be regarded as a measure for the flow. The spiral flow test was measured on a Demag ET100-310 with a closing pressure of 100 t and a 3 mm die.

The dimension and form stability of the polyethylene of the invention was tested by injection molding at 180 to 270° C. screw caps with screw diameter 28.2 mm. The caps were cooled and the screw diameter of 50 samples measured, the average calculated and compared to the original screw diameter. The samples were furthermore visually inspected for form and dimension stability.

The polyethylene of the invention showed high flow properties, with spiral lengths above 40 cm, measured at stock temperature of 250° C., an injection pressure of 1000 bar, screw speed 90 mm/s, mold temperature of 30° C. and wall thickness 2 mm.

Injection molding, preferably closures, caps and screw closures and caps, tube shoulders and engineering parts in which the polyethylene of the invention is present as a significant component are ones which contain from 50 to 100% by weight, preferably from 60 to 90% by weight, of the polyethylene of the invention, based on the total polymer material used for manufacture. The screw caps and closures are preferably used for bottles, preferably bottles for beverages.

The polyethylene of the invention is obtainable using the catalyst system of the invention and in particular its preferred embodiments.

The present invention further provides a catalyst composition comprising at least two different polymerization catalysts of which A) is at least one polymerization catalyst based on a monocyclopentadienyl complex of a metal of groups 4-6 of the Periodic Table of the Elements whose cyclopentadienyl system is substituted by an uncharged donor (A1) or a hafnocene (A2) and B) is at least one polymerization catalyst based on an iron component having a tridentate ligand bearing at least two ortho, ortho-disubstituted aryl radicals (B).

The invention further provides a process for the polymerization of olefins in the presence of the catalyst composition of the invention.

For the purposes of the present invention, an uncharged donor is an uncharged functional group containing an element of group 15 or 16 of the Periodic Table.

Hafnocene catalyst components are, for example, cyclopentadienyl complexes. The cyclopentadienyl complexes can be, for example, bridged or unbridged biscyclopentadienyl complexes as described, for example, in EP 129 368, EP 561 479, EP 545 304 and EP 576 970, monocyclopentadienyl complexes such as bridged amidocyclopentadienyl complexes described, for example, in EP 416 815, multinuclear cyclopentadienyl complexes as described in EP 632 063, pi-ligand-substituted tetrahydropentalenes as described in EP 659 758 or pi-ligand-substituted tetrahydroindenes as described in EP 661 300.

Preference is given to monocyclopentadienyl complexes (A1) containing the following structural feature of the general formula Cp-Y_(m)M^(A) (I), where the variables have the following meanings:

-   Cp is a cyclopentadienyl system, -   Y is a substituent which is bound to Cp and contains at least one     uncharged donor containing at least one atom of group 15 or 16 of     the Periodic Table, -   M^(A) is titanium, zirconium, hafnium, vanadium, niobium, tantalum,     chromium, molybdenum or tungsten, in particular chromium, and -   m is 1, 2 or 3.

Suitable monocyclopentadienyl complexes (A1) contain the structural element of the general formula Cp-Y_(m)M^(A) (I), where the variables are as defined above. Further ligands can therefore be bound to the metal atom M^(A). The number of further ligands depends, for example, on the oxidation state of the metal atom. These ligands are not further cyclopentadienyl systems. Suitable ligands include monoanionic and dianionic ligands as have been described, for example, for X. In addition, Lewis bases such as amines, ethers, ketones, aldehydes, esters, sulfides or phosphines can also be bound to the metal center M. The monocyclopentadienyl complexes can be in monomeric, dimeric or oligomeric form. The monocyclopentadienyl complexes are preferably in monomeric form.

M^(A) is a metal selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten. The oxidation state of the transition metals M^(A) in catalytically active complexes is usually known to those skilled in the art. Chromium, molybdenum and tungsten are very probably present in the oxidation state +3, zirconium and hafnium in the oxidation state +4 and titanium in the oxidation state +3 or +4. However, it is also possible to use complexes whose oxidation state does not correspond to that of the active catalyst. Such complexes can then be appropriately reduced or oxidized by means of suitable activators. M^(A) is preferably titanium in the oxidation state 3, vanadium, chromium, molybdenum or tungsten. Particular preference is given to chromium in the oxidation states 2, 3 and 4, in particular 3.

m can be 1, 2 or 3, i.e. 1, 2 or 3 donor groups Y may be bound to Cp, with these being able to be identical or different when 2 or 3 groups Y are present. Preference is given to only one donor group Y being bound to Cp (m=1).

The uncharged donor Y is an uncharged functional group containing an element of group 15 or 16 of the Periodic Table, e.g. an amine, imine, carboxamide, carboxylic ester, ketone (oxo), ether, thioketone, phosphine, phosphite, phosphine oxide, sulfonyl, sulfonamide or unsubstituted, substituted or fused, partially unsaturated heterocyclic or heteroaromatic ring systems. The donor Y can be bound intermolecularly or intramolecularly to the transition metal M^(A) or not be bound to it. The donor Y is preferably bound intramolecularly to the metal center M^(A). Particular preference is given to monocyclopentadienyl complexes containing the structural element of the general formula Cp-Y-M^(A).

Cp is a cyclopentadienyl system which may be substituted in any way and/or be fused with one or more aromatic, aliphatic, heterocyclic or heteroaromatic rings, with 1, 2 or 3 substituents, preferably 1 substituent, being formed by the group Y and/or 1, 2 or 3 substituents, preferably 1 substituent being substituted by the group Y and/or the aromatic, aliphatic, heterocyclic or heteroaromatic fused-on ring bearing 1, 2 or 3 substituents, preferably 1 substituent. The cyclopentadienyl skeleton itself is a C₅ ring system having 6 π electrons, in which one of the carbon atoms may also be replaced by nitrogen or phosphorus, preferably phosphorus. Preference is given to using C₅ ring systems without replacement by a heteroatom. This cyclopentadienyl skeleton can be, for example, fused with a heteroaromatic containing at least one atom from the group consisting of N, P, O and S or with an aromatic. In this context, fused means that the heterocycle and the cyclopentadienyl skeleton share two atoms, preferably carbon atoms. The cyclopentadienyl system is bound to M^(A).

Particularly well-suited monocyclopentadienyl complexes (A1) are ones in which Y is formed by the group -Z_(k)-A- and together with the cyclopentadienyl system Cp and M^(A) forms a monocyclopentadienyl complex containing the structural element of the general formula Cp-Z_(k)-A-M^(A) (II), where the variables have the following meanings:

-   Cp-Z_(k)-A is     where the variables have the following meanings: -   E^(1A)-E^(5A) are each carbon or not more than one E^(1A) to E^(5A)     phosphorus, -   R^(1A)-R^(4A) are each, independently of one another, hydrogen,     C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl radical and 6-20 carbon atoms in the     aryl radical, NR^(5A) ₂, N(SiR^(5A) ₃)₂, OR^(5A), OSiR^(5A) ₃,     SiR^(5A) ₃, BR^(5A) ₂, where the organic radicals R^(1A)-R^(4A) may     also be substituted by halogens and two vicinal radicals     R^(1A)-R^(4A) may also be joined to form a five-, six- or     seven-membered ring, and/or two vicinal radicals R^(1A)-R^(4A) are     joined to form a five-, six- or seven-membered heterocycle     containing at least one atom from the group consisting of N, P, O     and S, -   the radicals R^(5A) are each, independently of one another,     hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl     having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon     atoms in the aryl part and two geminal radicals R^(5A) may also be     joined to form a five- or six-membered ring, -   Z is a divalent bridge between A and Cp which is selected from the     following group     where -   L^(1A)-L^(3A) are each, independently of one another, silicon or     germanium, -   R^(6A)-R^(11A) are each, independently of one another, hydrogen,     C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part or SiR^(12A) ₃, where the organic radicals R^(6A)-R^(11A)     may also be substituted by halogens and two geminal or vicinal     radicals R^(6A)-R^(11A) may also be joined to form a five- or     six-membered ring and -   the radicals R^(12A) are each, independently of one another,     hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl or alkylaryl     having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon     atoms in the aryl part, C₁-C₁₀-alkoxy or C₆-C₁₀-aryloxy and two     radicals R^(12A) may also be joined to form a five- or six-membered     ring, and -   A is an uncharged donor group containing one or more atoms of group     15 and/or 16 of the Periodic Table of the Elements, preferably an     unsubstituted, substituted or fused, heteroaromatic ring system, -   M^(A) is a metal selected from the group consisting of titanium in     the oxidation state 3, vanadium, chromium, molybdenum and tungsten,     in particular chromium, and -   k is 0 or 1.

In preferred cyclopentadienyl systems Cp, all E^(1A) to E^(5A) are carbon.

The polymerization behavior of the metal complexes can be influenced by varying the substituents R^(1A)-R^(4A). The number and type of substituents can influence the accessibility of the metal atom M for the olefins to be polymerized. In this way, it is possible to modify the activity and selectivity of the catalyst in respect of various monomers, in particular bulky monomers. Since the substituents can also influence the rate of termination reactions of the growing polymer chain, the molecular weight of the polymers formed can also be altered in this way. The chemical structure of the substituents R^(1A) to R^(4A) can therefore be varied within a wide range in order to achieve the desired results and to obtain a tailored catalyst system. Possible carboorganic substituents R^(1A)-R^(4A) are, for example, the following: hydrogen, C₁-C₂₂-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₁-C₁₀-alkyl group and/or C₆-C₁₀-aryl group as substituent, e.g. cyclopropyl cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₂-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₂-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphenyl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphenyl, or arylalkyl which may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where two radicals R^(1A) to R^(4A) may also be joined to form a 5-, 6- or 7-membered ring and/or two vicinal radicals R^(1A)-R^(4A) may be joined to form a five-, six- or seven-membered heterocycle containing at least one atom from the group consisting of N, P, O and S and/or the organic radicals R^(1A)-R^(4A) may also be substituted by halogens such as fluorine, chlorine or bromine. Furthermore, R^(1A)-R^(4A) may be amino NR^(5A) ₂ or N(SiR^(5A) ₃)₂, alkoxy or aryloxy OR^(5A), for example dimethylamino, N-pyrrolidinyl, picolinyl, methoxy, ethoxy or isopropoxy. The radicals R^(5A) in organosilicone substituents SiR^(5A) ₃ can be the same carboorganic radicals as described above for R^(1A)-R^(4A), where two radicals R^(5A) may also be joined to form a 5- or 6-membered ring, e.g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, tritert-butylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. These SiR^(5A) ₃ radicals may also be joined to the cyclopentadienyl skeleton via an oxygen or nitrogen, for example trimethylsilyloxy, triethylsilyloxy, butyldimethylsilyloxy, tributylsilyloxy or tritert-butylsilyloxy. Preferred radicals R^(1A)-R^(4A) are hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, ortho-dialkyl- or -dichloro-substituted phenyls, trialkyl- or trichloro-substituted phenyls, naphthyl, biphenyl and anthranyl. Possible organosilicon substituents are, in particular, trialkylsilyl groups having from 1 to 10 carbon atoms in the alkyl radical, in particular trimethylsilyl groups.

Two vicinal radicals R^(1A)-R^(4A) together with the E^(1A)-E^(5A) bearing them may form a heterocycle, preferably heteroaromatic, containing at least one atom from the group consisting of nitrogen, phosphorus, oxygen and sulfur, particularly preferably nitrogen and/or sulfur, with the E^(1A)-E^(5A) present in the heterocycle or heteroaromatic preferably being carbons. Preference is given to heterocycles and heteroaromatics having a ring size of 5 or 6 ring atoms. Examples of 5-membered heterocycles which may contain from one to four nitrogen atoms and/or a sulfur or oxygen atom as ring atoms in addition to carbon atoms are 1,2-dihydrofuran, furan, thiophene, pyrrole, isoxazole, 3-isothiazole, pyrazole, oxazole, thiazole, imidazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-triazole and 1,2,4-triazole. Examples of 6-membered heteroaryl groups which may contain from one to four nitrogen atoms and/or a phosphorus atom are pyridine, phosphabenzene, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine 1,2,4-triazine or 1,2,3-triazine. The 5-membered and 6-membered heterocycles may also be substituted by C₁-C₁₀-alkyl, C₆-C₁₀-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-10 carbon atoms in the aryl part, trialkylsilyl or halogens such as fluorine, chlorine or bromine, dialkylamide, alkylarylamide, diarylamide, alkoxy or aryloxy or be fused with one or more aromatics or heteroaromatics. Examples of benzo-fused 5-membered heteroaryl groups are indole, indazole, benzofuran, benzothiophene, benzothiazole, benzoxazole and benzimidazole. Examples of benzo-fused 6-membered heteroaryl groups are chroman, benzopyran, quinoline, isoquinoline, cinnoline, phthalazine, quinazoline, quinoxaline, 1,10-phenanthroline and quinolizine. Naming and numbering of the heterocycles has been taken from Leftau, Chemie der Heterocyclen, 1 st edition, VEB, Weinheim 1979. The heterocycles/heteroaromatics are preferably fused with the cyclopentadienyl skeleton via a C—C double bond of the heterocycle/heteroaromatic. Heterocycles/heteroaromatics having one heteroatom are preferably 2,3- or b-fused.

Cyclopentadienyl systems Cp having a fused-on heterocycle are, for example, thiapentalene, 2-methylthiapentalene, 2-ethylthiapentalene, 2-isopropylthiapentalene, 2-n-butylthiapentalene, 2-tert-butylthiapentalene, 2-trimethylsilylthiapentalene, 2-phenylthiapentalene, 2-naphthylthiapentalene, 3-methylthiopentalene, 4-phenyl-2,6-dimethyl-1-thiopentalene, 4-phenyl-2,6-diethyl-1-thiopentalene, 4-phenyl-2,6-diisopropyl-1-thiopentalene, 4-phenyl-2,6-di-n-butyl-1-thiopentalene, 4-phenyl-2,6-ditrimethylsilyl-1-thiopentalene, azapentalene, 2-methylazapentalene, 2-ethylazapentalene, 2-isopropylazapentalene, 2-n-butylazapentalene, 2-trimethylsilylazapentalene, 2-phenylazapentalene, 2-naphthylazapentalene, 1-phenyl-2,5-dimethyl-1-azapentalene, 1-phenyl-2,5-diethyl-1-azapentalene, 1-phenyl-2,5-di-n-butyl-1-azapentalene, 1-phenyl-2,5-di-tert-butyl-1-azapentalene, 1-phenyl-2,5-di-trimethylsilyl-1-azapentalene, 1-tert-butyl-2,5-dimethyl-1-azapentalene, oxapentalene, phosphapentalene, 1-phenyl-2,5-dimethyl-1-phosphapentalene, 1-phenyl-2,5-diethyl-1-phosphapentalene, 1-phenyl-2,5-di-n-butyl-1-phosphapentalene, 1-phenyl-2,5-ditert-butyl-1-phosphapentalene, 1-phenyl-2,5-di-trimethylsilyl-1-phosphapentalene, 1-methyl-2,5-dimethyl-1-phosphapentalene, 1-tert-butyl-2,5-dimethyl-1-phosphapentalene, 7-cyclopenta-[1,2]thiophene[3,4]cyclopentadiene or 7-cyclopenta[1,2]pyrrol[3,4]cyclopentadiene.

In further preferred cyclopentadienyl systems Cp, the four radicals R^(1A)-R^(4A), i.e. the two pairs of vicinal radicals, form two heterocycles, in particular heteroaromatics. The heterocyclic systems are the same as those described above.

Cyclopentadienyl systems Cp having two fused heterocycles are, for example, 7-cyclopentadithiophene, 7-cyclopentadipyrrole or 7-cyclopentadiphosphole.

The synthesis of such cyclopentadienyl systems having a fused-on heterocycle is described, for example, in the abovementioned WO 98/22486. In “metalorganic catalysts for synthesis and polymerisation”, Springer Verlag 1999, Ewen et al., p. 150 ff describe further syntheses of these cyclopentadienyl systems.

Particularly preferred substituents R^(1A)-R^(4A) are the carboorganic substituents described above and the carboorganic substituents which form a cyclic fused ring system, i.e. together with the E^(1A)-E^(5A)-cyclopentadienyl skeleton, preferably a C₅-cyclopentadienyl skeleton, form, for example, an unsubstituted or substituted indenyl, benzindenyl, phenanthrenyl, fluorenyl or tetrahydroindenyl system, and also, in particular, their preferred embodiments.

Examples of such cyclopentadienyl systems (without the group -Z-A-, which is preferably located in the 1 position) are 3-methylcyclopentadienyl, 3-ethylcyclopentadienyl, 3-isopropylcyclopentadienyl, 3-tert-butylcyclopentadienyl, dialkylalkylcyclopentadienyl such as tetrahydroindenyl, 2,4-dimethylcyclopentadienyl or 3-methyl-5-tert-butylcyclopentadienyl, trialkylcyclopentadienyl such as 2,3,5-trimethylcyclopentadienyl or tetraalkylcyclopentadienyl such as 2,3,4,5-tetramethylcyclopentadienyl, and also indenyl, 2-methylindenyl, 2-ethylindenyl, 2-isopropylindenyl, 3-methylindenyl, benzindenyl and 2-methylbenzindenyl. The fused ring system may bear further C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, NR^(5A) ₂, N(SiR^(5A) ₃)₂, OR^(5A), OSiR^(5A) ₃ or SiR^(5A) ₃, e.g. 4-methylindenyl, 4-ethylindenyl, 4-isopropylindenyl, 5-methylindenyl, 4-phenylindenyl, 5-methyl-4-phenylindenyl, 2-methyl-4-phenylindenyl or 4-naphthylindenyl.

In a particularly preferred embodiment, one of the substituents R^(1A)-R^(4A), preferably R^(2A), is a C₆-C₂₂-aryl or an alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, preferably C₆-C₂₂-aryl such as phenyl, naphthyl, biphenyl, anthracenyl or phenanthrenyl, where the aryl may also be substituted by N-, P-, O- or S-containing substituents, C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, halogens or haloalkyls or haloaryls having 1-10 carbon atoms, for example o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphenyl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphenyl, o-, m-, p-dimethylaminophenyl, o-, m-, p-methoxyphenyl, o-, m-, p-fluorophenyl, o-, m-, p-chlorophenyl, o-, m-, p-trifluoromethylphenyl, 2,3-, 2,4-, 2,5- or 2,6-difluorophenyl, 2,3-, 2,4-, 2,5- or 2,6-dichlorophenyl or 2,3-, 2,4-, 2,5- or 2,6-di(trifluoromethyl)-phenyl. The N-, P-, O- or S-containing substituents, C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, halogens or haloalkyls or haloaryls having 1-10 carbon atoms as substituents on the aryl radical are preferably located in the para position relative to the bond to the cyclopentadienyl ring. The aryl substituent can be bound in the vicinal position relative to the substituent -Z-A or the two substituents are located relative to one another in the 1,3 positions on the cyclopentadienyl ring. -Z-A and the aryl substituent are preferably present in the 1,3 positions relative to one another on the cyclopentadienyl ring.

As in the case of the metallocenes, the monocyclopentadienyl complexes (A1) can be chiral. Thus, one of the substituents R^(1A)-R^(4A) of the cyclopentadienyl skeleton can have one or more chiral centers or the cyclopentadienyl system Cp itself can be enantiotopic so that chirality is induced only when it is bound to the transition metal M (for the formalism regarding chirality in cyclopentadienyl compounds, see R. Halterman, Chem. Rev. 92, (1992), 965-994).

The bridge Z between the cyclopentadienyl system Cp and the uncharged donor A is a divalent organic bridge (k=1) which preferably consists of carbon- and/or silicon- and/or boron-containing bridge members. The activity of the catalyst can be influenced by changing the length of the linkage between the cyclopentadienyl system and A. Z is preferably bound to the cyclopentadienyl skeleton next to the fused-on heterocycle or fused-on aromatic. Thus, if the heterocycle or aromatic is fused on in the 2,3 positions of the cyclopentadienyl skeleton, then Z is preferably located in the 1 or 4 position of the cyclopentadienyl skeleton.

Possible carboorganic substituents R^(6A)-R^(11A) on the linkage Z are, for example, the following: hydrogen, C₁-C₂₀-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₆-C₁₀-aryl group as substituent, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₀-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₀-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphen-1-yl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphen-1-yl, or arylalkyl which may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where two R^(6A) to R^(11A) may also be joined to form a 5- or 6-membered ring, for example cyclohexane, and the organic radicals R^(6A)-R^(11A) may also be substituted by halogens such as fluorine, chlorine or bromine, for example pentafluorophenyl or bis-3,5-trifluoromethylphen-1-yl and alkyl or aryl.

The radicals R^(12A) in organosilicon substitutents SiR^(12A) ₃ can be the same radicals as mentioned above for R^(6A)-R^(11A), where two radicals R^(12A) may also be joined to form a 5- or 6-membered ring, e.g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, tritert-butylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. Preferred radicals R^(6A)-R^(11A) are hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, benzyl, phenyl, ortho-dialkyl- or dichloro-substituted phenyls, trialkyl- or trichloro-substituted phenyls, naphthyl, biphenyl and anthranyl.

Particularly preferred substituents R^(6A) to R^(11A) are hydrogen, C₁-C₂₀-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, C₆-C₂₀-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphen-1-yl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphen-1-yl, or arylalkyl which may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl where two radicals R^(6A) to R^(11A) may also be joined to form a 5- or 6-membered ring, for example cyclohexane, and the organic radicals R^(6A)-R^(2B) may also be substituted by halogens such as fluorine, chlorine or bromine, in particular fluorine, for example pentafluorophenyl or bis-3,5-trifluoromethylphen-1-yl and alkyl or aryl. Particular preference is given to methyl, ethyl, 1-propyl, 2-isopropyl, 1-butyl, 2-tert-butyl, phenyl and pentafluorophenyl.

Z is preferably a group —CR^(6A)R^(7A), —SiR^(6A)R^(7A)—, in particular —Si(CH₃)₂—, —CR^(6A)R^(7A)CR^(8A)R^(9A) —SiR^(6A)R^(7A) CR^(8A)R^(9A)— or substituted or unsubstituted 1,2-phenylene and in particular —CR^(6A)R^(7A)—. The preferred embodiments of the substituents R^(6A) to R^(11A) described above are likewise preferred embodiments here. Preference is given to —CR^(6A)R^(7A)— being a —CHR^(6A)—, —CH₂— or —C(CH₃)₂— group. The group —SiR^(6A)R^(7A)— in -L^(1A)R^(6A)R^(7A)CR^(8A)R^(9A)— can be bound to the cyclopentadienyl system or to A. This group —SiR^(6A)R^(7A)— or a preferred embodiment thereof is preferably bound to Cp.

k is 0 or 1; in particular, k is 1 or when A is an unsubstituted, substituted or fused, heterocyclic ring system may also be 0. Preference is given to k being 1.

A is an uncharged donor containing an atom of group 15 or 16 of the Periodic Table, preferably one or more atoms selected from the group consisting of oxygen, sulfur, nitrogen and phosphorus, preferably nitrogen and phosphorus. The donor function in A can bind intermolecularly or intramolecularly to the metal M^(A). The donor in A is preferably bound intramolecularly to M. Possible donors are uncharged functional groups containing an element of group 15 or 16 of the Periodic Table, e.g. amine, imine, carboxamide, carboxylic ester, ketone (oxo), ether, thioketone, phosphine, phosphite, phosphine oxide, sulfonyl, sulfonamide or unsubstituted, substituted or fused, heterocyclic ring systems. The attachment of A to the cyclopentadienyl radical and Z can be carried out synthetically by, for example, a method analogous to that described in WO 00/35928.

A is preferably a group selected from among —OR^(13A)—SR^(13A)—NR^(13A)R^(14A)—, —PR^(13A)R^(14A)—, —C═NR^(13A)— and unsubstituted, substituted or fused heteroaromatic ring systems, in particular —NR^(13A)R^(14A)—, —C═NR^(13A)— and unsubstituted, substituted or fused heteroaromatic ring systems.

R^(13A) and R^(14A) are each, independently of one another, hydrogen, C₁-C₂₀-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₆-C₁₀-aryl group as substituent, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₀-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₀-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphen-1-yl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphen-1-yl, alkylaryl which has from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl or SiR^(15A) ₃, where the organic radicals R^(13A)-R^(14A) may also be substituted by halogens such as fluorine, chlorine or bromine or nitrogen-containing groups and further C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR^(15A) ₃ groups and two vicinal radicals R^(13A)-R^(14A) may also be joined to form a five- or six-membered ring and the radicals R^(15A) are each, independently of one another, hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two radicals R^(15A) may also be joined to form a five- or six-membered ring. NR^(13A)R^(14A) is an amide substituent. It is preferably a secondary amide such as dimethylamide, N-ethylmethylamide, diethylamide, N-methylpropylamide, N-methylisopropylamide, N-ethylisopropylamide, dipropylamide, diisopropylamide, N-methylbutylamide, N-ethylbutylamide, N-methyl-tert-butylamide, N-tert-butylisopropylamide, dibutylamide, di-sec-butylamide, diisobutylamide, tert-amyl-tert-butylamide, dipentylamide, N-methylhexylamide, dihexylamide, tert-amyl-tert-octylamide, dioctylamide, bis(2-ethylhexyl)amide, didecylamide, N-methyloctadecylamide, N-methylcyclohexylamide, N-ethylcyclohexylamide, N-isopropylcyclohexylamide, N-tert-butylcyclohexylamide, dicyclohexylamide, pyrrolidine, piperidine, hexamethylenimine, decahydroquinoline, diphenylamine, N-methylanilide or N-ethylanilide.

In the imino group —C═NR^(13A), R^(13A) is preferably a C₆-C₂₀-aryl radical which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphen-1-yl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphen-1-yl.

A is preferably an unsubstituted, substituted or fused heteroaromatic ring system which can contain heteroatoms from the group consisting of oxygen, sulfur, nitrogen and phosphorus in addition to ring carbons. Examples of 5-membered heteroaryl groups which may contain from one to four nitrogen atoms or from one to three nitrogen atoms and/or a sulfur or oxygen atom as ring members in addition to carbon atoms are 2-furyl, 2-thienyl, 2-pyrrolyl, 3-isoxazolyl, 5-isoxazolyl, 3-isothiazolyl, 5-isothiazolyl, 1-pyrazolyl, 3-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 1,2,4-oxadiazol-3-yl, 1,2,4-oxadiazol-5-yl, 1,3,4-oxadiazol-2-yl and 1,2,4-triazol-3-yl. Examples of 6-membered hetero-aryl groups which may contain from one to four nitrogen atoms and/or a phosphorus atom are 2-pyridinyl, 2-phosphabenzenyl, 3-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 2-pyrazinyl, 1,3,5-triazin-2-yl and 1,2,4-triazin-3-yl, 1,2,4-triazin-5-yl and 1,2,4-triazin-6-yl. The 5-membered and 6-membered heteroaryl groups may also be substituted by C₁-C₁₀-alkyl, C₆-C₁₀-aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-10 carbon atoms in the aryl part, trialkylsilyl or halogens such as fluorine, chlorine or bromine or be fused with one or more aromatics or heteroaromatics. Examples of benzo-fused 5-membered heteroaryl groups are 2-indolyl, 7-indolyl, 2-coumaronyl, 7-coumaronyl, 2-thionaphthenyl, 7-thionaphthenyl, 3-indazolyl, 7-indazolyl, 2-benzimidazolyl and 7-benzimidazolyl. Examples of benzo-fused 6-membered heteroaryl groups are 2-quinolyl, 8-quinolyl, 3-cinnolyl, 8-cinnolyl, 1-phthalazyl, 2-quinazolyl, 4-quinazolyl, 8-quinazolyl, 5-quinoxalyl, 4-acridyl, 1-phenanthridyl and 1-phenazyl. Naming and numbering of the heterocycles has been taken from L. Fieser and M. Fieser, Lehrbuch der organischen Chemie, 3^(rd) revised edition, Verlag Chemie, Weinheim 1957.

Among these heteroaromatic systems A, particular preference is given to unsubstituted, substituted and/or fused six-membered heteroaromatics having 1, 2, 3, 4 or 5 nitrogen atoms in the heteroaromatic part, in particular substituted and unsubstituted 2-pyridyl or 2-quinolyl. A is therefore preferably a group of the formula (IV)

, where

-   E^(6A)-E^(9A) are each, independently of one another, carbon or     nitrogen, -   R^(16A)-R^(19A) are each, independently of one another, hydrogen,     C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part or SiR^(20A)3, where the organic radicals R^(16A)-R^(19A)     may also be substituted by halogens or nitrogen and further     C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part or SiR^(20A) ₃ and two vicinal radicals R^(16A)-R^(19A) or     R^(16A) and Z may also be joined to form a five- or six-membered     ring and -   the radicals R^(20A) are each, independently of one another,     hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl or alkylaryl     having from 1 to 10 carbon atoms in the alkyl radical and 6-20     carbon atoms in the aryl radical and two radicals R^(20A) may also     be joined to form a five- or six-membered ring and -   p is 0 when E^(6A)-E^(9A) is nitrogen and is 1 when E^(6A)-E^(9A) is     carbon.

In particular, 0 or 1 E^(6A)-E^(9A) are nitrogen and the remainder are carbon. A is particularly preferably a 2-pyridyl, 6-methyl-2-pyridyl, 4-methyl-2-pyridyl, 5-methyl-2-pyridyl, 5-ethyl-2-pyridyl, 4,6-dimethyl-2-pyridyl, 3-pyridazyl, 4-pyrimidyl, 2-pyrazinyl, 6-methyl-2-pyrazinyl, 5-methyl-2-pyrazinyl, 3-methyl-2-pyrazinyl, 3-ethylpyrazinyl, 3,5,6-trimethyl-2-pyrazinyl, 2-quinolyl, 4-methyl-2-quinolyl, 6-methyl-2-quinolyl, 7-methyl-2-quinolyl, 2-quinoxalyl or 3-methyl-2-quinoxalyl.

Owing to the ease of preparation, preferred combinations of Z and A are those in which Z is unsubstituted or substituted 1,2-phenylene and A is NR^(16A)R^(17A) and those in which Z is —CHR^(6A)—, —CH₂—, —C(CH₃)₂ or —Si(CH₃)₂— and A is unsubstituted or substituted 2-quinolyl or unsubstituted or substituted 2-pyridyl. Systems without a bridge Z, in which k is 0, are also very particularly simple to synthesize. A is preferably unsubstituted or substituted 8-quinolyl in this case. In addition, when k is 0, R^(2A) is preferably a C₆-C₂₂-aryl or an alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, preferably C₆-C₂₂-aryl such as phenyl, naphthyl, biphenyl, anthracenyl or phenanthrenyl, where the aryl may also be substituted by N-, P-, O- or S-containing substituents, C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, halogens or haloalkyls or haloaryls having 1-10 carbon atoms.

The preferred embodiments described above for the variables are also preferred in these preferred combinations.

M^(A) is a metal selected from the group consisting of titanium in the oxidation state 3, vanadium, chromium, molybdenum and tungsten, preferably titanium in the oxidation state 3 and chromium. Particular preference is given to chromium in the oxidation states 2, 3 and 4, in particular 3. The metal complexes, in particular the chromium complexes, can be obtained in a simple manner by reacting the appropriate metal salts, e.g. metal chlorides, with the ligand anion (e.g. using a method analogous to the examples in DE 197 10615).

Among the suitable monocyclopentadienyl complexes (A1), preference is given to those of the formula Cp-Y_(m)M^(A)X_(n) (V) where the variables Cp, Y, A, m and M^(A) are as defined above and their preferred embodiments are also preferred here and:

-   X^(A) are each, independently of one another, fluorine, chlorine,     bromine, iodine, hydrogen, C₁-C₁₀-alkyl, C₂-C₁₀-alkenyl,     C₆-C₂₀-aryl, alkylaryl having 1-10 carbon atoms in the alkyl part     and 6-20 carbon atoms in the aryl part, NR^(21A)R^(22A), OR^(21A),     SR^(21A), SO₃R^(21A), OC(O)R^(21A), CN, SCN, β-diketonate, CO, BF₄     ⁻, PF₆ ⁻ or a bulky noncoordinating anion or two radicals X^(A) form     a substituted or unsubstituted diene ligand, in particular a     1,3-diene ligand, and the radicals X^(A) may be joined to one     another, -   R^(21A)-R^(22A) are each, independently of one another, hydrogen,     C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part, SiR^(23A) ₃, where the organic radicals R^(21A)-R^(22A)     may also be substituted by halogens or nitrogen- and     oxygen-containing groups and two radicals R^(21A)-R^(22A) may also     be joined to form a five- or six-membered ring, -   the radicals R^(23A) are each, independently of one another,     hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl     having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon     atoms in the aryl part and two radicals R^(23A) may also be joined     to form a five- or six-membered ring and -   n is 1, 2, or 3.

The embodiments and preferred embodiments described above for Cp, Y, Z, A, m and M^(A) also apply individually and in combination to these preferred monocyclopentadienyl complexes.

The ligands X^(A) result, for example, from the choice of the appropriate starting metal compounds used for the synthesis of the monocyclopentadienyl complexes, but can also be varied afterwards. Possible ligands X^(A) are, in particular, the halogens such as fluorine, chlorine, bromine or iodine, especially chlorine. Alkyl radicals such as methyl, ethyl, propyl, butyl, vinyl, allyl, phenyl or benzyl are also advantageous ligands X^(A). Further ligands X^(A) which may be mentioned, purely by way of example and in no way exhaustively, are trifluoroacetate, BF₄ ⁻, PF₆ ⁻ and also weakly coordinating or noncoordinating anions (cf., for example, S. Strauss in Chem. Rev. 1993, 93, 927-942), e.g. B(C₆F₅)₄ ⁻.

Amides, alkoxides, sulfonates, carboxylates and β-diketonates are also particularly useful ligands X^(A). Variation of the radicals R^(21A) and R^(22A) enables, for example, physical properties such as solubility to be finely adjusted. Possible carboorganic substituents R^(21A)-R^(22A) are, for example, the following: C₁-C₂₀-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₆-C₁₀-aryl group as substituent, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₀-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₀-aryl which may be substituted by further alkyl groups and/or N- or O-containing radicals, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphenyl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphenyl, 2-methoxyphenyl, 2-N,N-dimethylaminophenyl or arylalkyl, where the arylalkyl may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where R^(21A) may also be joined to R^(22A) to form a 5- or 6-membered ring and the organic radicals R^(21A)-R^(22A) may also be substituted by halogens such as fluorine, chlorine or bromine. Possible radicals R^(23A) in organosilicon substituents SiR^(23A) ₃ are the same radicals as have been mentioned above for R^(21A)-R^(22A), where two R^(23A) may also be joined to form a 5- or 6-membered ring, e.g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. Preference is given to using C₁-C₁₀-alkyl such as methyl, ethyl, n-propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and also vinyl allyl, benzyl and phenyl as radicals R^(21A) and R^(22A). Some of these substituted ligands X are particularly preferably used since they are obtainable from cheap and readily available starting materials. Thus, a particularly preferred embodiment is that in which X^(A) is dimethylamide, methoxide, ethoxide, isopropoxide, phenoxide, naphthoxide, triflate, p-toluenesulfonate, acetate or acetylacetonate.

The number n of ligands X^(A) depends on the oxidation state of the transition metal M^(A). The number n can thus not be given in general terms. The oxidation state of transition metals M^(A) in catalytically active complexes is usually known to those skilled in the art. Chromium, molybdenum and tungsten are very probably present in the oxidation state +3, vanadium in the oxidation state +3 or +4. However, it is also possible to use complexes whose oxidation state does not correspond to that of the active catalyst. Such complexes can then be appropriately reduced or oxidized by means of suitable activators. Preference is given to using chromium complexes in the oxidation state +3 and titanium complexes in the oxidation state 3.

Preferred monocyclopentadienyl complexes (A1) of this type are 1-(8-quinolyl)-3-phenylcyclopentadienylchromium(III) dichloride, 1-(8-quinolyl)-3-(1-naphthyl)cyclopentadienylchromium(III) dichloride, 1-(8-quinolyl)-3-(4-trifluoromethylphenyl)cyclopentadienylchromium(III) dichloride, 1-(8-quinolyl)-2-methyl-3-phenylcyclopentadienylchromium(III) dichloride, 1-(8-quinolyl)-2-methyl-3-(1-naphthyl)cyclopentadienylchromium(III) dichloride, 1-(8-quinolyl)-2-methyl-3-(4-trifluoromethylphenyl)cyclopentadienylchromium(III) dichloride, 1-(8-quinolyl)-2-phenylindenylchromium(III) dichloride, 1-(8-quinolyl)-2-phenylbenzindenylchromium(III) dichloride, 1-(8-(2-methylquinolyl))-2-methyl-3-phenylcyclopentadienylchromium(III) dichloride, 1-(8-(2-methylquinolyl))-2-phenylindenylchromium(III) dichloride, 1-(2-pyridylmethyl)-3-phenylcyclopentadienylchromium(III) dichloride, 1-(2-pyridylmethyl)-2-methyl-3-phenylcyclopentadienylchromium(III) dichloride, 1-(2-quinolylmethyl)-3-phenylcyclopentadienylchromium dichloride, 1-(2-pyridylethyl)-3-phenylcyclopentadienylchromium dichloride, 1-(2-pyridyl-1-methylethyl)-3-phenylcyclopentadienylchromium dichloride, 1-(2-pyridyl-1-phenylmethyl)-3-phenylcyclopentadienylchromium dichloride, 1-(2-pyridylmethyl)-indenylchromium(III) dichloride, 1-(2-quinolylmethyl)indenylchromium dichloride, 1-(2-pyridylethyl)indenylchromium dichloride, 1-(2-pyridyl-1-methylethyl)indenylchromium dichloride, 1-(2-pyridyl-1-phenylmethyl)indenylchromium dichloride, 5-[(2-pyridyl)methyl]-1,2,3,4-tetramethylcyclopentadienylchromium dichloride and 1-(8-(2-methylquinolyl))-2-methylbenzindenylchromium(III) dichloride.

The preparation of such functional cyclopentadienyl ligands is known. Various synthetic routes to these complexing ligands are described by, for example, M. Enders et al., in Chem. Ber. (1996), 129, 459-463 or P. Jutzi and U. Siemeling in J. Orgmet. Chem. (1995), 500, 175-185.

The synthesis of such complexes can be carried out by methods known per se, with the reaction of the appropriately substituted, cyclic hydrocarbon anions with halides of titanium, vanadium or chromium being preferred. Examples of appropriate preparative methods are described, for example, in Journal of Organometallic Chemistry, 369 (1989), 359-370 and in EP-A-1212333.

Particularly suitable hafnocenes (A2) are hafnium complexes of the general formula (VI)

where the substituents and indices have the following meanings:

-   X^(B) is fluorine, chlorine, bromine, iodine, hydrogen,     C₁-C₁₀-alkyl, C₂-C₁₀-alkenyl, C₆-C₁₅-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and from 6 to 20 carbon atoms     in the aryl part, —OR^(6B) or —NR^(6B)R^(7B), or two radicals X^(B)     form a substituted or unsubstituted diene ligand, in particular a     1,3-diene ligand, and the radicals X^(B) are identical or different     and may be joined to one another, -   E^(1B)-E^(5B) are each carbon or not more than one E^(1B) to E^(5B)     is phosphorus or nitrogen, preferably carbon, -   t is 1, 2 or 3 and is, depending on the valence of Hf, such that the     metallocene complex of the general formula (VI) is uncharged,     where -   R^(6B) and R^(7B) are each C₁-C₁₀-alkyl, C₆-C₁₅-aryl, alkylaryl,     arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10 carbon     atoms in the alkyl part and from 6 to 20 carbon atoms in the aryl     part and -   R^(1B) to R^(5B) are each, independently of one another hydrogen,     C₁-C₂₂-alkyl, 5- to 7-membered cycloalkyl or cycloalkenyl which may     in turn bear C₁-C₁₀-alkyl groups as substituents, C₂-C₂₂-alkenyl,     C₆-C₂₂-aryl, arylalkyl having from 1 to 16 carbon atoms in the alkyl     part and from 6 to 21 carbon atoms in the aryl part, NR⁸², N(SiR³)₂,     OR^(8B), OSiR^(8B) ₃, SiR^(8B) ₃, where the organic radicals     R^(1B)-R^(5B) may also be substituted by halogens and/or two     radicals R^(1B)-R^(5B), in particular vicinal radicals, may also be     joined to form a five-, six- or seven-membered ring, and/or two     vicinal radicals R^(1D)-R^(5D) may be joined to form a five-, six-     or seven-membered heterocycle containing at least one atom from the     group consisting of N, P, O and S, where -   the radicals R^(8B) can be identical or different and can each be     C₁-C₁₀-alkyl, C₃-C₁₀-cycloalkyl, C₆-C₁₅-aryl, C₁-C₄-alkoxy or     C₆-C₁₀-aryloxy and -   Z^(1B) is X^(B) or     where the radicals -   R^(9B) to R^(13B) are each, independently of one another, hydrogen,     C₁-C₂₂-alkyl, 5- to 7-membered cycloalkyl or cycloalkenyl which may     in turn bear C₁-C₁₀-alkyl groups as substituents, C₂-C₂₂-alkenyl,     C₆-C₂₂-aryl, arylalkyl having from 1 to 16 carbon atoms in the alkyl     part and 6-21 carbon atoms in the aryl part, NR^(14B) ₂, N(SiR^(14B)     ₃)₂, OR^(14B), OSiR^(14B) ₃, SiR^(14B) ₃, where the organic radicals     R^(9B)-R^(13B) may also be substituted by halogens and/or two     radicals R^(9B)-R^(13B), in particular vicinal radicals, may also be     joined to form a five-, six- or seven-membered ring, and/or two     vicinal radicals R^(9B)-R^(13B) may be joined to form a five-, six-     or seven-membered heterocycle containing at least one atom from the     group consisting of N, P, O and S, where -   the radicals R^(14B) are identical or different and are each     C₁-C₁₀-alkyl, C₃-C₁₀-cycloalkyl, C₆-C₁₅-aryl, C₁-C₄-alkoxy or     C₆-C₁₀-aryloxy, -   E^(6B)-E^(10B) are each carbon or not more than one E^(6B) to     E^(10B) is phosphorus or nitrogen, preferably carbon, -   or where the radicals R^(4B) and Z^(1B) together form an —R^(15B)     _(v)-A^(1B)-group, where -   R^(15B) is     where -   R^(16B)-R^(21B) are identical or different and are each a hydrogen     atom, a halogen atom, a trimethylsilyl group, a C₁-C₁₀-alkyl group,     a C₁-C₁₀-fluoroalkyl group, a C₆-C₁₀-fluoroaryl group, a C₆-C₁₀-aryl     group, a C₁-C₁₀-alkoxy group, a C₇-C₁₅-alkylaryloxy group, a     C₂-C₁₀-alkenyl group, a C₇-C₄₀-arylalkyl group, a C₈-C₄₀-arylalkenyl     group or a C₇-C₄₀-alkylaryl group or two adjacent radicals together     with the atoms connecting them form a saturated or unsaturated ring     having from 4 to 15 carbon atoms, and -   M^(2B)-M^(4B) are each silicon, germanium or tin, or preferably     silicon, -   A^(1B) is     —NR^(22B) ₂, —PR^(22B) ₂ or an unsubstituted, substituted or fused,     heterocyclic ring system, where -   the radicals R^(22B) are each, independently of one another,     C₁-C₁₀-alkyl, C₆-C₁₅-aryl, C₃-C₁₀-cycloalkyl, C₇-C₁₈-alkylaryl or     Si(R^(23B))₃, -   R^(23B) is hydrogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl which may in turn     bear C₁-C₄-alkyl groups as substituents or C₃-C₁₀-cycloalkyl, -   v is 1 or when A^(1B) is an unsubstituted, substituted or fused,     heterocyclic ring system may also be 0     or where the radicals R^(4B) and R^(12B) together form an     —R^(15B)-group.     A^(1B) can, for example together with the bridge R^(15B), form an     amine, ether, thioether or phosphine. However, A^(1B) can also be an     unsubstituted, substituted or fused, heterocyclic aromatic ring     system which can contain heteroatoms from the group consisting of     oxygen, sulfur, nitrogen and phosphorus in addition to ring carbons.     Examples of 5-membered heteroaryl groups which can contain from one     to four nitrogen atoms and/or a sulfur or oxygen atom as ring     members in addition to carbon atoms are 2-furyl, 2-thienyl,     2-pyrrolyl, 3-isoxazolyl, 5-isoxazolyl, 3-isothiazolyl,     5-isothiazolyl, 1-pyrazolyl, 3-pyrazolyl, 5-pyrazolyl, 2-oxazolyl,     4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl,     2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 1,2,4-oxadiazol-3-yl,     1,2,4-oxadiazol-5-yl, 1,3,4-oxadiazol-2-yl and 1,2,4-triazol-3-yl.     Examples of 6-membered heteroaryl groups which may contain from one     to four nitrogen atoms and/or a phosphorus atom are 2-pyridinyl,     2-phosphabenzenyl, 3-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl,     2-pyrazinyl, 1,3,5-triazin-2-yl and 1,2,4-triazin-3-yl,     1,2,4-triazin-5-yl and 1,2,4-triazin-6-yl. The 5-membered and     6-membered heteroaryl groups may also be substituted by     C₁-C₁₀-alkyl, C₆-C₁₀-aryl, alkylaryl having from 1 to 10 carbon     atoms in the alkyl part and 6-10 carbon atoms in the aryl part,     trialkylsilyl or halogens such as fluorine, chlorine or bromine or     be fused with one or more aromatics or heteroaromatics. Examples of     benzo-fused 5-membered heteroaryl groups are 2-indolyl, 7-indolyl,     2-coumaronyl, 7-coumaronyl, 2-thionaphthenyl, 7-thionaphthenyl,     3-indazolyl, 7-indazolyl, 2-benzimidazolyl and 7-benzimidazolyl.     Examples of benzo-fused 6-membered heteroaryl groups are 2-quinolyl,     8-quinolyl, 3-cinnolyl, 8-cinnolyl, 1-phthalazyl, 2-quinazolyl,     4-quinazolyl, 8-quinazolyl, 5-quinoxalyl, 4-acridyl, 1-phenanthridyl     and 1-phenazyl. Naming and numbering of the heterocycles has been     taken from L. Fieser and M. Fieser, Lehrbuch der organischen Chemie,     3^(rd) revised edition, Verlag Chemie, Weinheim 1957.

The radicals X^(B) in the general formula (XIV) are preferably identical, preferably fluorine, chlorine, bromine, C₁-C₇-alkyl or aralkyl, in particular chlorine, methyl or benzyl.

The synthesis of such complexes can be carried out by methods known per se, with the reaction of the appropriately substituted cyclic hydrocarbon anions with halides of hafnium being preferred. Examples of appropriate preparative methods are described, for example, in Journal of Organometallic Chemistry, 369 (1989), 359-370.

The hafnocenes can be used in the Rac or pseudo-Rac form. The term pseudo-Rac refers to complexes in which the two cyclopentadienyl ligands are in the Rac arrangement relative to one another when all other substituents of the complex are disregarded.

Examples of suitable hafnocenes (A2) are, inter alia, methylenebis(cyclopentadienyl)hafnium dichloride, methylenebis(3-methylcyclopentadienyl)hafnium dichloride, methylenebis(3-n-butylcyclopentadienyl)hafnium dichloride, methylenebis(indenyl)hafnium dichloride, methylenebis(tetrahydroindenyl) hafnium dichloride, isopropylidenebis(cyclopentadienyl)hafnium dichloride, isopropylidenebis(3-trimethylsilylcyclopentadienyl)hafnium dichloride, isopropylidenebis(3-methylcyclopentadienyl)hafnium dichloride, isopropylidenebis(3-n-butylcyclopentadienyl)hafnium dichloride, isopropylidenebis(3-phenylcyclopentadienyl)hafnium dichloride, isopropylidenebis(indenyl)hafnium dichloride, isopropylidenebis(tetrahydroindenyl)hafnium dichloride, dimethylsilanediylbis(cyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(indenyl)hafnium dichloride, dimethylsilanediylbis(tetrahydroindenyl)hafnium dichloride, ethylenebis(cyclopentadienyl)hafnium dichloride, ethylenebis(indenyl)hafnium dichloride, ethylenebis(tetrahydroindenyl)hafnium dichloride, tetramethylethylene-9-fluorenylcyclopentadienylhafnium dichloride, dimethylsilanediylbis(tetramethylcyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(3-trimethylsilylcyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(3-methylcyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(3-n-butylcyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(3-tert-butyl-5-methylcyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(3-tert-butyl-5-ethylcyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(2-methylindenyl)hafnium dichloride, dimethylsilanediylbis(2-isopropylindenyl)hafnium dichloride, dimethylsilanediylbis(2-tert-butylindenyl)hafnium dichloride, diethylsilanediylbis(2-methylindenyl)hafnium dibromide, dimethylsilanediylbis(3-methyl-5-methylcyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(3-ethyl-5-isopropylcyclopentadienyl)hafnium dichloride, dimethylsilanediylbis(2-ethylindenyl)hafnium dichloride, dimethylsilanediylbis(2-methyl-4,5-benzindenyl)hafnium dichloride, dimethylsilanediylbis(2-ethyl-4,5-benzindenyl)hafnium dichloride, methylphenylsilanediylbis(2-methyl-4,5-benzindenyl)hafnium dichloride, methylphenylsilanediylbis(2-ethyl-4,5-benzindenyl)hafnium dichloride, diphenylsilanediylbis(2-methyl-4,5-benzindenyl)hafnium dichloride, diphenylsilanediylbis(2-ethyl-4,5-benzindenyl)hafnium dichloride, diphenylsilanediylbis(2-methylindenyl)hafnium dichloride, dimethylsilanediylbis(2-methyl-4-phenylindenyl)hafnium dichloride, dimethylsilanediylbis(2-ethyl-4-phenylindenyl)hafnium dichloride, dimethylsilanediylbis(2-methyl-4-(1-naphthyl)indenyl)hafnium dichloride, dimethylsilanediylbis(2-ethyl-4-(1-naphthyl)indenyl)hafnium dichloride, dimethylsilanediylbis(2-propyl-4-(1-naphthyl)indenyl)hafnium dichloride, dimethylsilanediylbis(2-i-butyl-4-(1-naphthyl)indenyl)hafnium dichloride, dimethylsilanediylbis(2-propyl-4-(9-phenanthryl)indenyl)hafnium dichloride, dimethylsilanediylbis(2-methyl-4-isopropylindenyl)hafnium dichloride, dimethylsilanediylbis(2,7-dimethyl-4-isopropylindenyl)hafnium dichloride, dimethylsilanediylbis(2-methyl-4,6-diisopropylindenyl)hafnium dichloride, dimethylsilanediylbis(2-methyl-4[p-trifluoromethylphenyl]indenyl)hafnium dichloride, dimethylsilanediylbis(2-methyl-4-[3′,5′-dimethylphenyl]indenyl)hafnium dichloride, dimethylsilanediylbis(2-methyl-4-[4′-tert-butylphenyl]indenyl)hafnium dichloride, diethylsilanediylbis(2-methyl-4-[4′-tert-butylphenyl]indenyl)hafnium dichloride, dimethylsilanediylbis(2-ethyl-4-[4′-tert-butylphenyl]indenyl)hafnium dichloride, dimethylsilanediylbis(2-propyl-4-[4′-tert-butylphenyl]indenyl)hafnium dichloride, dimethylsilanediylbis(2-isopropyl-4-[4′-tert-butylphenyl]-indenyl)hafnium dichloride, dimethylsilanediyl(2-isopropyl-4-phenylindenyl)(2-methyl-4-phenylindenyl)hafnium dichloride, dimethylsilanediyl(2-isopropyl-4-(1-naphthyl)indenyl)(2-methyl-4-(1-naphthyl)indenyl)hafnium dichloride, dimethylsilanediyl(2-isopropyl-4-[4′-tert-butylphenyl]indenyl)(2-methyl-4-[4′-tert-butylphenyl]indenyl)hafnium dichloride, dimethylsilanediyl(2-isopropyl-4-[4′-tert-butylphenyl]indenyl)(2-methyl-4-[1′-naphthyl]indenyl)hafnium dichloride and ethylene(2-isopropyl-4-[4′-tert-butylphenyl]indenyl)(2-methyl-4-[4′-tert-butylphenyl]indenyl)hafnium dichloride, and also the corresponding dimethylhafnium, monochloromono(alkylaryloxy)hafnium and di(alkylaryloxy)hafnium compounds. The complexes can be used in the rac form, the meso form or as mixtures of these.

Among the hafnocenes of the general formula (VI), those of the formula (VII)

are preferred.

Among the compounds of the formula (VII), preference is given to those in which

X^(B) is fluorine, chlorine, bromine, C₁-C₄-alkyl or benzyl, or two radicals X^(B) form a substituted or unsubstituted butadiene ligand,

-   t is 1 or 2, preferably 2, -   R^(1B) to R^(5B) are each hydrogen, C₁-C₈-alkyl, C₆-C₈-aryl, NR^(8B)     ₂, OSiR^(8B) ₃ or Si(R^(8B))₃ and -   R^(9B) to R^(13B) are each hydrogen, C₁-C₈-alkyl or C₆-C₈-aryl,     NR^(14B) ₂, OSiR^(14B) ₃ or Si(R^(14B))₃     or in each case two radicals R^(1B) to R^(5B) and/or R^(9B) to     R^(13B) together with the C₅ ring form an indenyl, fluorenyl or     substituted indenyl or fluorenyl system.

The hafnocenes of the formula (VII) in which the cyclopentadienyl radicals are identical are particularly useful.

Examples of particularly suitable compounds D) of the formula (VII) are, inter alia: bis(cyclopentadienyl)hafnium dichloride, bis(indenyl)hafnium dichloride, bis(fluorenyl)hafnium dichloride, bis(tetrahydroindenyl)hafnium dichloride, bis(pentamethylcyclopentadienyl)hafnium dichloride, bis(trimethylsilylcyclopentadienyl)hafnium dichloride, bis(trimethoxysilylcyclopentadienyl)hafnium dichloride, bis(ethylcyclopentadienyl)hafnium dichloride, bis(isobutylcyclopentadienyl)hafnium dichloride, bis(3-butenylcyclopentadienyl)hafnium dichloride, bis(methylcyclopentadienyl)hafnium dichloride, bis(1,3-di-tert-butylcyclopentadienyl)hafnium dichloride, bis(trifluoromethylcyclopentadienyl)hafnium dichloride, bis(tert-butylcyclopentadienyl)hafnium dichloride, bis(n-butylcyclopentadienyl)hafnium dichloride, bis(phenylcyclopentadienyl)hafnium dichloride, bis(N,N-dimethylaminomethylcyclopentadienyl)hafnium dichloride, bis(1,3-dimethylcyclopentadienyl)hafnium dichloride, bis(1-n-butyl-3-methylcyclopentadienyl)hafnium dichloride, (cyclopentadienyl)(methylcyclopentadienyl)hafnium dichloride, (cyclopentadienyl)(n-butylcyclopentadienyl)hafnium dichloride, (methylcyclopentadienyl)(n-butylcyclopentadienyl)hafnium dichloride, (cyclopentadienyl)(1-methyl-3-n-butylcyclopentadienyl)hafnium dichloride, bis(tetramethylcyclopentadienyl)hafnium dichloride and also the corresponding dimethylhafnium compounds. Further examples are the corresponding hafnocene compounds in which one or two of the chloride ligands have been replaced by bromide or iodide.

Suitable catalysts B) are transition metal complexes with at least one ligand of the general formulae XV to XIX,

where the variables have the following meanings:

-   E^(1C) is nitrogen or phosphorus, in particular nitrogen, -   E^(2C)-E^(4C) are each, independently of one another, carbon,     nitrogen or phosphorus, in particular carbon, -   R^(1C)-R^(3C) are each, independently of one another, hydrogen     C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part, halogen, NR^(18C) ₂, OR^(18C), SiR^(19C) ₃, where the     organic radicals R^(1C)-R^(3C) may also be substituted by halogens     and/or two vicinal radicals R^(1C)-R^(3C) may also be joined to form     a five-, six- or seven-membered ring, and/or two vicinal radicals     R^(1C)-R^(3C) are joined to form a five-, six- or seven-membered     heterocycle containing at least one atom from the group consisting     of N, P, O and S, -   R^(4C)-R^(7C) are each, independently of one another, hydrogen,     C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part, NR^(18C) ₂, SiR^(19C) ₃, where the organic radicals     R^(4c)-R^(7C) may also be substituted by halogens and/or two geminal     or vicinal radicals R^(4C)-R^(7C) may also be joined to form a     five-, six- or seven-membered ring, and/or two geminal or vicinal     radicals R^(4C)-R^(9C) are joined to form a five-, six- or     seven-membered heterocycle containing at least one atom from the     group consisting of N, P, O and S, and when v is 0, R^(6C) is a bond     to L^(1C) and/or R^(7C) is a bond to L^(2C) so that L^(1C) forms a     double bond to the carbon atom bearing R^(4C) and/or L^(2C) forms a     double bond to the carbon atom bearing R^(5C), -   u is 0 when E^(2C)-E^(4C) is nitrogen or phosphorus and is 1 when     E^(2C)-E^(4C) is carbon, -   L^(1C)-L^(2C) are each, independently of one another, nitrogen or     phosphorus, in particular nitrogen, -   R^(8C)-R^(11C) are each, independently of one another, C₁-C₂₂-alkyl,     C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1 to 10 carbon     atoms in the alkyl part and 6-20 carbon atoms in the aryl part,     halogen, NR^(18C) ₂, OR^(18C), SiR^(19C) ₃, where the organic     radicals R^(8C)-R^(11C) may also be substituted by halogens and/or     two vicinal radicals R^(8C)-R^(17C) may also be joined to form a     five-, six- or seven-membered ring, and/or two vicinal radicals     R^(8C)-R^(17C) are joined to form a five-, six- or seven-membered     heterocycle containing at least one atom from the group consisting     of N, P, O and S, -   R^(12C)R^(17C) are each, independently of one another, hydrogen,     C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part, halogen, NR^(18C) ₂, OR^(18C), SiR^(19C) ₃, where the     organic radicals R^(12C)-R^(17C) may also be substituted by halogens     and/or two vicinal radicals R^(8C)-R^(17C) may also be joined to     form a five-, six- or seven-membered ring, and/or two vicinal     radicals R^(8C)-R^(17C) are joined to form a five-, six- or     seven-membered heterocycle containing at least one atom from the     group consisting of N, P, O and S, -   the indices v are each, independently of one another, 0 or 1, -   the radicals X^(C) are each, independently of one another, fluorine,     chlorine, bromine, iodine, hydrogen, C₁-C₁₀-alkyl, C₂-C₁₀-alkenyl,     C₆-C₂₀-aryl, alkylaryl having 1-10 carbon atoms in the alkyl part     and 6-20 carbon atoms in the aryl part, NR^(18C) ₂, OR^(18C),     SR^(18C), SO₃R^(18C), OC(O)R^(18C), CN, SCN, β-diketonate, CO, BF₄     ⁻, PF₆ ⁻ or a bulky noncoordinating anion and the radicals X^(C) may     be joined to one another, -   the radicals R^(18C) are each, independently of one another,     hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl     having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon     atoms in the aryl part, SiR^(19C) ₃, where the organic radicals     R^(18C) may also be substituted by halogens or nitrogen- and     oxygen-containing groups and two radicals R^(18C) may also be joined     to form a five- or six-membered ring, -   the radicals R^(19C) are each, independently of one another,     hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl     having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon     atoms in the aryl part, where the organic radicals R^(19C) may also     be substituted by halogens or nitrogen- and oxygen-containing groups     and two radicals R^(19C) may also be joined to form a five- or     six-membered ring, -   s is 1, 2, 3 or 4, in particular 2 or 3, -   D is an uncharged donor and -   t is from 0 to 4, in particular 0, 1 or 2.

The three atoms E^(2C) to E^(4C) in a molecule can be identical or different. If E^(1C) is phosphorus, then E^(2C) to E^(4c) are preferably each carbon. If E^(1C) is nitrogen, then E^(2C) to E^(4C) are each preferably nitrogen or carbon, in particular carbon.

The substituents R^(1C)-R^(3C) and R^(8C)-R^(17C) can be varied within a wide range. Possible carboorganic substituents R^(1C)-R^(3C) and R^(8C)-R^(17C) are, for example, the following: C₁-C₂₂-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₁-C₁₀-alkyl group and/or C₆-C₁₀-aryl group as substituents, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₂-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₂-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphenyl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphenyl, or arylalkyl which may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where two radicals R^(1C) to R^(3C) and/or two vicinal radicals R^(8C)-R^(17C) may also be joined to form a 5-, 6- or 7-membered ring and/or two of the vicinal radicals R^(1C)-R^(3C) and/or two of the vicinal radicals R^(8C)-R^(17C) may be joined to form a five-, six- or seven-membered heterocycle containing at least one atom from the group consisting of N, P, O and S and/or the organic radicals R^(1C)-R^(3C) and/or R^(8C)-R^(17C) may also be substituted by halogens such as fluorine, chlorine or bromine. Furthermore, R^(1C)-R^(3C) and R^(8C)-R^(17C) can also be amino NR^(18C) ₂ or N(SiR^(19C) ₃)₂, alkoxy or aryloxy OR^(18C), for example dimethylamino, N-pyrrolidinyl, picolinyl, methoxy, ethoxy or isopropoxy or halogen such as fluorine, chlorine or bromine. Possible radicals R^(19C) in organosilicon substituents SiR^(19C) ₃ are the same carboorganic radicals as have been described above for R^(1C)-R^(3C), where two R^(19C) may also be joined to form a 5- or 6-membered ring, e.g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, tri-tert-butysilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. These SiR^(19C) ₃ radicals may also be bound to E^(2C)-E^(4C) via an oxygen or nitrogen, for example trimethylsilyloxy, triethylsilyloxy, butyldimethylsilyloxy, tributylsilyloxy or tri-tert-butylsilyloxy.

Preferred radicals R^(1C)-R^(3C) are hydrogen, methyl, trifluoromethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, ortho-dialkyl- or -dichloro-substituted phenyls, trialkyl- or trichloro-substituted phenyls, naphthyl, biphenyl and anthranyl. Particularly preferred organosilicon substituents are trialkylsilyl groups having from 1 to 10 carbon atoms in the alkyl radical, in particular trimethylsilyl groups.

Preferred radicals R^(12C)-R^(17C) are hydrogen, methyl, trifluoromethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, fluorine, chlorine and bromine, in particular hydrogen. In particular, R^(13C) and R^(16C) are each methyl, trifluoromethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, fluorine, chlorine or bromine and R^(12C), R^(14C), R^(15C) and R^(17C) are each hydrogen.

Preferred radicals R^(8C)-R^(11C) are methyl, trifluoromethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, fluorine, chlorine and bromine. In particular, R^(8C) and R^(10C) are each a C₁-C₂₂-alkyl which may also be substituted by halogens, in particular a C₁-C₂₂-n-alkyl which may also be substituted by halogens, e.g. methyl, trifluoromethyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, or a halogen such as fluorine, chlorine or bromine and R^(9C) and R^(11C) are each a halogen such as fluorine, chlorine or bromine. Particular preference is given to R^(8C) and R^(10C) each being a C₁-C₂₂-alkyl which may also be substituted by halogens, in particular a C₁-C₂₂-n-alkyl which may also be substituted by halogens, e.g. methyl, trifluoromethyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl and R^(9C) and R^(11C) are each a halogen such as fluorine, chlorine or bromine.

In particular, R^(12C), R^(14C); R^(15C) and R^(17C) are identical, R^(13C) and R^(16C) are identical, R^(9C) and R^(11C) are identical and R^(8C) and R^(10C) are identical. This is also preferred in the preferred embodiments described above.

The substituents R^(4C)-R^(7C), too, can be varied within a wide range. Possible carboorganic substituents R^(4C)-R^(7C) are, for example, the following: C₁-C₂₂-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₁-C₁₀-alkyl group and/or C₆-C₁₀-aryl group as substituent, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₂-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₂-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphenyl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphenyl, or arylalkyl, where the arylalkyl may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where two radicals R^(4C) to R^(7C) may also be joined to form a 5-, 6- or 7-membered ring and/or two geminal radicals R^(4C)-R^(7C) may be joined to form a five-, six- or seven-membered heterocycle containing at least one atom from the group consisting of N, P, O and S and/or the organic radicals R^(4C)-R^(7C) may also be substituted by halogens such as fluorine, chlorine or bromine. Furthermore, R^(4C)-R^(7C) may be amino NR^(18C) ₂ or N(SiR^(19C) ₃)₂, for example dimethylamino, N-pyrrolidinyl or picolinyl. Possible radicals R^(19C) in organosilicone substituents SiR^(19C) ₃ are the same carboorganic radicals as have been described above for R^(1C)-R^(3C), where two R^(19C) may also be joined to form a 5- or 6-membered ring, e.g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, tri-tert-butylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. These SiR^(19C) ₃ radicals can also be bound via nitrogen to the carbon bearing them. When v is 0, R^(6C) is a bond to L^(1C) and/or R^(7C) is a bond to L^(2C), so that L^(1C) forms a double bond to the carbon atom bearing R^(4C) and/or L^(2C) forms a double bond to the carbon atom bearing R^(5C).

Preferred radicals R^(4C)-R^(7C) are hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, benzyl, phenyl, ortho-dialkyl- or dichloro-substituted phenyls, trialkyl- or trichloro-substituted phenyls, naphthyl, biphenyl and anthranyl. Preference is also given to amide substituents NR^(18C) ₂, in particular secondary amides such as dimethylamide, N-ethylmethylamide, diethylamide, N-methylpropylamide, N-methylisopropylamide, N-ethylisopropylamide, dipropylamide, diisopropylamide, N-methylbutylamide, N-ethylbutylamide, N-methyl-tert-butylamide, N-tert-butylisopropylamide, dibutylamide, di-sec-butylamide, diisobutylamide, tert-amyl-tert-butylamide, dipentylamide, N-methylhexylamide, dihexylamide, tert-amyl-tert-octylamide, dioctylamide, bis(2-ethylhexyl)amide, didecylamide, N-methyloctadecylamide, N-methylcyclohexylamide, N-ethylcyclohexylamide, N-isopropylcyclohexylamide, N-tert-butylcyclohexylamide, dicyclohexylamide, pyrrolidine, piperidine, hexamethylenimine, decahydroquinoline, diphenylamine, N-methylanilide or N-ethylanilide.

L^(1C) and L^(2C) are each, independently of one another, nitrogen or phosphorus, in particular nitrogen, and when v is 0 can form a double bond with the carbon atom bearing R^(4C) or R^(5C). In particular, when v is 0, L^(1C) and/or L^(2C) together with the carbon atom bearing R^(4C) or R^(5C) form an imino group —CR^(4C)═N— or —CR^(5C)═N—. When v is 1, L^(1C) and/or L^(2C) together with the carbon atom bearing R^(4C) or R^(5C) forms, in particular, an amido group —CR^(4C)R^(6C)—N⁻— or —CR^(5C)R^(7C)—N⁻—.

The ligands X^(C) result, for example, from the choice of the appropriate starting metal compounds used for the synthesis of the iron complexes, but can also be varied afterward. Possible ligands X^(C) are, in particular, the halogens such as fluorine, chlorine, bromine or iodine, in particular chlorine. Alkyl radicals such as methyl, ethyl, propyl, butyl, vinyl, allyl, phenyl or benzyl are also usable ligands X^(C). As further ligands X^(C), mention may be made, purely by way of example and in no way exhaustively, of trifluoroacetate, BF₄ ⁻, PF₆ ⁻ and weakly coordinating or noncoordinating anions (cf., for example, S. Strauss in Chem. Rev. 1993, 93, 927-942), e.g. B(C₆F₅)₄ ⁻. Amides, alkoxides, sulfonates, carboxylates and β-diketonates are also particularly useful ligands X^(C). Some of these substituted ligands X are particularly preferably used since they are obtainable from cheap and readily available starting materials. Thus, a particularly preferred embodiment is that in which X^(C) is dimethylamide, methoxide, ethoxide, isopropoxide, phenoxide, naphthoxide, triflate, p-toluenesulfonate, acetate or acetylacetonate.

Variation of the radicals R^(18C) enables, for example, physical properties such as solubility to be finely adjusted. Possible carboorganic substituents R^(18C) are, for example, the following: C₁-C₂₀-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₆-C₁₀-aryl group as substituent, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₀-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₀-aryl which may be substituted by further alkyl groups and/or N- or O-containing radicals, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphenyl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphenyl, 2-methoxyphenyl, 2-N,N-dimethylaminophenyl, or arylalkyl which may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where two radicals R^(18C) may also be joined to form a 5- or 6-membered ring and the organic radicals R^(18C) may also be substituted by halogens such as fluorine, chlorine or bromine. Possible radicals R^(19C) in organosilicon substituents SiR^(19C) ₃ are the same radicals which have been described above for R^(18C), where two radicals R^(19C) may also be joined to form a 5- or 6-membered ring, e.g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. Preference is given to using C₁-C₁₀-alkyl such as methyl, ethyl, n-propyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and also vinyl allyl, benzyl and phenyl as radicals R^(18C).

The number s of the ligands X^(C) depends on the oxidation state of the iron. The number s can thus not be given in general terms. The oxidation state of the iron in catalytically active complexes is usually known to those skilled in the art. However, it is also possible to use complexes whose oxidation state does not correspond to that of the active catalyst. Such complexes can then be appropriately reduced or oxidized by means of suitable activators. Preference is given to using iron complexes in the oxidation state +3 or +2.

D is an uncharged donor, in particular an uncharged Lewis base or Lewis acid, for example amines, alcohols, ethers, ketones, aldehydes, esters, sulfides or phosphines which may be bound to the iron center or else still be present as residual solvent from the preparation of the iron complexes.

The number t of the ligands D can be from 0 to 4 and is often dependent on the solvent in which the iron complex is prepared and the time for which the resulting complexes are dried and can therefore also be a nonintegral number such as 0.5 or 1.5. In particular, t is 0, 1 to 2.

In a preferred embodiment are

where

-   E^(2C)-E^(4C) are each, independently of one another, carbon,     nitrogen or phosphorus, in particular carbon, -   R^(1C)-R^(3C) are each, independently of one another, hydrogen,     C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part, halogen, NR^(18C) ₂, OR^(18C), SiR^(19C) ₃, where the     organic radicals R^(1C)-R^(3C) may also be substituted by halogens     and/or two vicinal radicals R^(1C)-R^(3C) may also be joined to form     a five-, six- or seven-membered ring, and/or two vicinal radicals     R^(1C)-R^(3C) are bound to form a five-, six- or seven-membered     heterocycle containing at least one atom from the group consisting     of N, P, O and S, -   R^(4C)-R^(5C) are each, independently of one another, hydrogen,     C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part, NR^(18C) ₂, SiR^(19C) ₃, where the organic radicals     R^(4C)-R^(5C) may also be substituted by halogens, -   u is 0 when E^(2C)-E^(4C) is nitrogen or phosphorus and is 1 when     E^(2C)-E^(4C) is carbon, -   L^(1C)-L^(2C) are each, independently of one another, nitrogen or     phosphorus, in particular nitrogen, -   R^(8C)-R^(11C) are each, independently of one another, C₁-C₂₂-alkyl,     C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1 to 10 carbon     atoms in the alkyl part and 6-20 carbon atoms in the aryl part,     halogen, NR^(18C) ₂, OR^(18C), SiR^(19C) ₃, where the organic     radicals R^(8C)-R^(11C) may also be substituted by halogens and/or     two vicinal radicals R^(8C)-R^(17C) may also be joined to form a     five-, six- or seven-membered ring, and/or two vicinal radicals     R^(8C)-R^(17C) are joined to form a five-, six- or seven-membered     heterocycle containing at least one atom from the group consisting     of N, P, O and S, -   R^(12C)-R^(17C) are each, independently of one another, hydrogen,     C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl, C₆-C₂₂-aryl, alkylaryl having from 1     to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the     aryl part, halogen, NR^(18C) ₂, OR^(18C), SiR^(19C) ₃, where the     organic radicals R^(12C)-R^(17C) may also be substituted by halogens     and/or two vicinal radicals R^(8C)-R^(17C) may also be joined to     form a five-, six- or seven-membered ring, and/or two vicinal     radicals R^(8C)-R^(17C) are joined to form a five-, six- or     seven-membered heterocycle containing at least one atom from the     group consisting of N, P, O or S, -   the indices v are each, independently of one another, 0 or 1, -   the radicals X^(C) are each, independently of one another, fluorine,     chlorine, bromine, iodine, hydrogen, C₁-C₁₀-alkyl, C₂-C₁₀-alkenyl,     C₆-C₂₀-aryl, alkylaryl having 1-10 carbon atoms in the alkyl part     and 6-20 carbon atoms in the aryl part, NR^(18C) ₂, OR^(18C),     SR^(18C), SO₃R^(18C), OC(O)R^(18C), CN, SCN, β-diketonate, CO, BF₄     ⁻, PF₆ ⁻ or a bulky noncoordinating anion and the radicals X^(C) may     be joined to one another, -   the radicals R^(18C) are each, independently of one another,     hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl     having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon     atoms in the aryl part, SiR^(19C) ₃, where the organic radicals     R^(18C) may also be substituted by halogens and nitrogen- and     oxygen-containing groups and two radicals R^(18C) may also be joined     to form a five- or six-membered ring, -   the radicals R^(19C) are each, independently of one another,     hydrogen, C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, C₆-C₂₀-aryl, alkylaryl     having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon     atoms in the aryl part, where the organic radicals R^(19C) may also     be substituted by halogens or nitrogen- and oxygen-containing groups     and two radicals R^(19C) may also be joined to form a five- or     six-membered ring, -   s is 1, 2, 3 or 4, in particular 2 or 3, -   D is an uncharged donor and -   t is from 0 to 4, in particular 0, 1 or 2.

The embodiments and preferred embodiments described above likewise apply to E^(2C)-E^(4C), R^(1C)-R^(3C), X^(C), R^(18C) and R^(19C).

The substituents R^(4C)-R^(5C) can be varied within a wide range. Possible carboorganic substituents R^(4C)-R^(5C) are, for example, the following: hydrogen, C₁-C₂₂-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₁-C₁₀-alkyl group and/or C₆-C₁₀-aryl group as substituent, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₂-alkenyl which may be linear, cyclic or branched and in which the double bond may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₂-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphenyl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphenyl, or arylalkyl which may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where the organic radicals R^(4C)-R^(5C) may also be substituted by halogens such as fluorine, chlorine or bromine. Furthermore, R^(4C)-R^(5C) can be amino NR^(18C) ₂ or N(SiR^(19C) ₃)₂, for example dimethylamino, N-pyrrolidinyl or picolinyl. Possible radicals R^(19C) in organosilicon substituents SiR^(19C) ₃ are the same carboorganic radicals as described above for R^(1C)-R^(3C), where two radicals R^(19C) may also be joined to form a 5- or 6-membered ring, e.g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, tritert-butylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. These SiR^(19C) ₃ radicals can also be bound via nitrogen to the carbon bearing them.

Preferred radicals R^(4C)-R^(5C) are hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl or benzyl, in particular methyl.

The substituents R^(8C)-R^(17C) can be varied within a wide range. Possible carboorganic substituents R^(8C)-R^(17C) are, for example, the following: C₁-C₂₂-alkyl which may be linear or branched, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, 5- to 7-membered cycloalkyl which may in turn bear a C₁-C₁₀-alkyl group and/or C₆-C₁₀-aryl group as substituent, e.g. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl or cyclododecyl, C₂-C₂₂-alkenyl which may be linear, cyclic or branched and in which the double may be internal or terminal, e.g. vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclopentenyl, cyclohexenyl, cyclooctenyl or cyclooctadienyl, C₆-C₂₂-aryl which may be substituted by further alkyl groups, e.g. phenyl, naphthyl, biphenyl, anthranyl, o-, m-, p-methylphenyl, 2,3-, 2,4-, 2,5- or 2,6-dimethylphenyl, 2,3,4-, 2,3,5-, 2,3,6-, 2,4,5-, 2,4,6- or 3,4,5-trimethylphenyl, or arylalkyl which may be substituted by further alkyl groups, e.g. benzyl, o-, m-, p-methylbenzyl, 1- or 2-ethylphenyl, where two radicals R^(8C) to R^(17C) may also be joined to form a 5-, 6- or 7-membered ring and/or two of the vicinal radicals R^(8C)-R^(17C) may be joined to form a five-, six- or seven-membered heterocycle containing at least one atom from the group consisting of N, P, O and S and/or the organic radicals R^(8C)-R^(17C) may also be substituted by halogens such as fluorine, chlorine or bromine. Furthermore, R^(8C)-R^(17C) can be halogen such as fluorine, chlorine, bromine, amino NR^(18C) ₂ or N(SiR^(19C) ₃)₂, alkoxy or aryloxy OR^(18C), for example dimethylamino, N-pyrrolidinyl, picolinyl, methoxy, ethoxy or isopropoxy. Possible radicals R^(19C) in organosilicon substituents SiR^(19C) ₃ are the same carboorganic radicals which have been mentioned above for R^(1C)-R^(3C), where two radicals R^(19C) may also be joined to form a 5- or 6-membered ring, e.g. trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylsilyl, tritert-butylsilyl, triallylsilyl, triphenylsilyl or dimethylphenylsilyl. These SiR^(19C) ₃ radicals can also be bound via an oxygen or nitrogen, for example trimethylsilyloxy, triethylsilyloxy, butyldimethylsilyloxy, tributylsilyloxy or tritert-butylsilyloxy.

Preferred radicals R^(12C)-R^(17C) are hydrogen, methyl, trifluoromethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, fluorine, chlorine and bromine, in particular hydrogen. In particular, R^(13C) and R^(16C) are each methyl, trifluoromethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, fluorine, chlorine or bromine and R^(12C), R^(14C), R^(15C) and R^(17C) are each hydrogen.

Preferred radicals R^(8C)-R^(11C) are methyl, trifluoromethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, fluorine, chlorine and bromine. In particular R^(8C) and R^(10C) are each a C₁-C₂₂-alkyl which may also be substituted by halogens, in particular a C₁-C₂₂-n-alkyl which may also be substituted by halogens, e.g. methyl, trifluoromethyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, or a halogen such as fluorine, chlorine or bromine and R^(9C) and R^(11C) are each a halogen such as fluorine, chlorine or bromine. Particular preference is given to R^(8C) and R^(10C) each being a C₁-C₂₂-alkyl which may also be substituted by halogens, in particular a C₁-C₂₂-n-alkyl which may also be substituted by halogens, e.g. methyl, trifluoromethyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl and R^(9C) and R^(11C) each being a halogen such as fluorine, chlorine or bromine.

In particular, R^(12C), R^(14C), R^(15C) and R^(17C) are identical, R^(13C) and R^(16C) are identical, R^(5C) and R^(11C) are identical and R^(8C) and R^(10C) are identical. This is also preferred in the preferred embodiments described above.

The preparation of the compounds B) is described, for example, in J. Am. Chem. Soc. 120, p. 4049 ff. (1998), J. Chem. Soc., Chem. Commun. 1998, 849, and WO 98/27124. Preferred complexes B) are 2,6-Bis[1-(2,6-dimethylphenylimino)ethyl]pyridine iron(II) dichloride, 2,6-Bis[1-(2,4,6-trimethylphenylimino)ethyl]pyridine iron(II) dichloride, 2,6-Bis[1-(2-chloro-6-methylphenylimino)ethyl]pyridine iron(II) dichloride, 2,6-Bis[1-(2,6-diisopropylphenylimino)ethyl]pyridine iron(II) dichloride, 2,6-Bis[1-(2,6-dichlorophenylimino)ethyl]pyridine iron(II) dichloride, 2,6-Bis[1-(2,6-diisopropyl phenylimino)methyl]pyridine iron(II) dichloride, 2,6-Bis[1-(2,4-dichloro-6-methylphenylimino)ethyl]pyridine iron(II) dichloride, 2,6-Bis[1-(2,6-difluorophenylimino)ethyl]pyridine iron(II) dichloride, 2,6-Bis[1-(2,6-difbromophenylimino)ethyl]pyridine iron(II) dichloride or the respective dibromides or tribromides.

In the following, reference to a transition metal complex (A) or catalyst (A) means a monocyclopentadienyl complex (A1) and/or a hafnocene (A2). The molar ratio of transition metal complex A) to polymerization catalyst B) is usually in the range from 1:100 to 100:1, preferably from 1:10 to 10:1 and particularly preferably from 1:5 to 5:1. When a transition metal complex A) is used as sole catalyst under the same reaction conditions in the homopolymerization or copolymerization of ethylene, it preferably produces a higher Mw than does the complex (B) when it is used as sole complex under the same reaction conditions. The preferred embodiments of the complexes (A1), (A2) and (B) are likewise preferred in combinations of complex (A1) and (B) and in the combination of complex (A2) and (B).

The catalyst composition of the invention can be used alone or together with further components as catalyst system for olefin polymerization. Furthermore, we have found catalyst systems for olefin polymerization comprising

-   A) at least one polymerization catalyst based on a     monocyclopentadienyl complex of a metal of groups 4-6 of the     Periodic Table of the Elements whose cyclopentadienyl system is     substituted by an uncharged donor (A1) or a hafnocene (A2), -   B) at least one polymerization catalyst based on an iron component     having a tridentate ligand bearing at least two ortho,     ortho-disubstituted aryl radicals, -   C) optionally one or more activating compounds, -   D) optionally one or more organic or inorganic supports, -   E) optionally one or more metal compounds of a metal of group 1, 2     or 13 of the Periodic Table.

In the following, reference to a transition metal complex (A) or catalyst (A) means a monocyclopentadienyl complex (A1) and/or a hafnocene (A2). The molar ratio of transition metal complex A) to polymerization catalyst B) is usually in the range from 1:100 to 100:1, preferably from 1:10 to 10:1 and particularly preferably from 1:5 to 5:1. When a transition metal complex A) is used as sole catalyst under the same reaction conditions in the homopolymerization or copolymerization of ethylene, it preferably produces a higher Mw than does the complex (B) when it is used as sole complex under the same reaction conditions. The preferred embodiments of the complexes (A1), (A2) and (B) are likewise preferred in combinations of complex (A1) and (B) and in the combination of complex (A2) and (B).

The monocyclopentadienyl complexes (A1), the hafnocene (A2) and/or the iron complex (B) sometimes have only a low polymerization activity and are then brought into contact with one or more activators, viz. the component (C), in order to be able to display a good polymerization activity. The catalyst system therefore optionally further comprises, as component (C) one or more activating compounds, preferably one or two activating compounds (C). The catalyst system of the invention preferably comprises one or more activators (C). Depending on the catalyst combinations (A) and (B), one or more activating compounds (C) are advantageous. The activation of the transition metal complex (A) and of the iron complex (B) of the catalyst composition can be carried out using the same activator or activator mixture or different activators. It is often advantageous to use the same activator (C) for both the catalysts (A) and (B).

The activator or activators (C) can in each case be used in any amounts based on the complexes (A) and (B) of the catalyst composition of the invention. They are preferably used in an excess or in stoichiometric amounts, in each case based on the complex (A) or (B) which they activate. The amount of activating compound(s) to be used depends on the type of the activator (C). In general, the molar ratio of transition metal complex (A) to activating compound (C) can be from 1:0.1 to 1:10000, preferably from 1:1 to 1:2000. The molar ratio of iron complex (B) to activating compound (C) is also usually in the range from 1:0.1 to 1:10000, preferably from 1:1 to 1:2000.

Suitable compounds (C) which are able to react with the transition metal complex (A) or the iron complex (B) to convert it into a catalytically active or more active compound are, for example, compounds such as an aluminoxane, a strong uncharged Lewis acid, an ionic compound having a Lewis-acid cation or an ionic compound containing a Brönsted acid as cation.

As aluminoxanes, it is possible to use, for example, the compounds described in WO 00/31090. Particularly useful aluminoxanes are open-chain or cyclic aluminoxane compounds of the general formula (X) or (XI)

where R^(1D)-R^(4D) are each, independently of one another, a C₁-C₆-alkyl group, preferably a methyl, ethyl, butyl or isobutyl group and I is an integer from 1 to 40, preferably from 4 to 25.

A particularly useful aluminoxane compound is methylaluminoxane.

These oligomeric aluminoxane compounds are usually prepared by controlled reaction of a solution of a trialkylaluminum, in particular trimethylaluminum, with water. In general, the oligomeric aluminoxane compounds obtained are in the form of mixtures of both linear and cyclic chain molecules of various lengths, so that I is to be regarded as a mean. The aluminoxane compounds can also be present in admixture with other metal alkyls, usually aluminum alkyls. Aluminoxane preparations suitable as component (C) are commercially available.

Furthermore modified aluminoxanes in which some of the hydrocarbon radicals have been replaced by hydrogen atoms or alkoxy, aryloxy, siloxy or amide radicals can also be used in place of the aluminoxane compounds of the formula (X) or (XI) as component (C).

It has been found to be advantageous to use the transition metal complex A) or the iron complex B) and the aluminoxane compounds in such amounts that the atomic ratio of aluminum from the aluminoxane compounds including any aluminum alkyl still present to the transition metal from the transition metal complex (A) is in the range from 1:1 to 2000:1, preferably from 10:1 to 500:1 and in particular in the range from 20:1 to 400:1. The atomic ratio of aluminum from the aluminoxane compounds including any aluminum alkyl still present to the iron from the iron complex (B) is usually in the range from 1:1 to 2000:1, preferably from 10:1 to 500:1 and in particular in the range from 20:1 to 400:1.

A further class of suitable activating components (C) are hydroxyaluminoxanes. These can be prepared, for example, by addition of from 0.5 to 1.2 equivalents of water, preferably from 0.8 to 1.2 equivalents of water, per equivalent of aluminum to an alkylaluminum compound, in particular triisobutylaluminum, at low temperatures, usually below 0° C. Such compounds and their use in olefin polymerization are described, for example, in WO 00/24787. The atomic ratio of aluminum from the hydroxyaluminoxane compound to the transition metal from the transition metal complex (A) or the iron complex (B) is usually in the range from 1:1 to 100:1, preferably from 10:1 to 50:1 and in particular in the range from 20:1 to 40:1. Preference is given to using a monocyclopentadienyl metal dialkyl compound (A1) or a hafnocene dialkyl compound (A2).

As strong, uncharged Lewis acids, preference is given to compounds of the general formula (XII) M^(2D)X^(1D)X^(2D)X^(3D)  (XII) where

-   M^(2D) is an element of group 13 of the Periodic Table of the     Elements, in particular B, Al or Ga, preferably B, -   X^(1D), X^(2D) and X^(3D) are each hydrogen, C₁-C₁₀-alkyl,     C₆-C₁₅-aryl, alkylaryl, arylalkyl, haloalkyl or haloaryl each having     from 1 to 10 carbon atoms in the alkyl part and from 6 to 20 carbon     atoms in the aryl part or fluorine, chlorine, bromine or iodine, in     particular haloaryls, preferably pentafluorophenyl.

Further examples of strong, uncharged Lewis acids are given in WO 00/31090.

Compounds which are particularly useful as component (C) are boranes and boroxins such as trialkylborane, triarylborane or trimethylboroxin. Particular preference is given to using boranes which bear at least two perfluorinated aryl radicals. Particular preference is given to compounds of the general formula (XII) in which X^(1D), X^(2D) and X^(3D) are identical, for example triphenylborane, tris(4-fluorophenyl)borane, tris(3,5-difluorophenyl)borane, tris(4-fluoromethylphenyl)borane, tris(pentafluorophenyl)borane, tris(tolyl)borane, tris(3,5-dimethylphenyl)borane, tris(3,5-difluorophenyl)borane or tris(3,4,5-trifluorophenyl)borane. Preference is given to using tris(pentafluorophenyl)borane.

Suitable compounds (C) are preferably prepared by reaction of aluminum or boron compounds of the formula (XII) with water, alcohols, phenol derivatives, thiophenol derivatives or aniline derivatives, with halogenated and especially perfluorinated alcohols and phenols being of particular importance. Examples of particularly useful compounds are pentafluorophenol, 1,1-bis(pentafluorophenyl)methanol and 4-hydroxy-2,2′,3,3′,4′,5,5′,6,6′-nonafluorobiphenyl. Examples of combinations of compounds of the formula (XII) with Broenstedt acids are, in particular, trimethylaluminum/pentafluorophenol, trimethylaluminum/1-bis(pentafluorophenyl)methanol, trimethylaluminum/4-hydroxy-2,2′,3,3′,4′,5,5′,6,6′-nonafluorobiphenyl, triethylaluminum/pentafluorophenol and triisobutylaluminum/pentafluorophenol and triethylaluminum/4,4′-dihydroxy-2,2′,3,3′,5,5′,6,6′-octafluorobiphenyl hydrate.

In further suitable aluminum and boron compounds of the formula (XII), R^(1D) is an OH group, such as, for example, in boronic acids and borinic acids. Particular mention may be made of borinic acids having perfluorinated aryl radicals, for example (C₆F₅)₂BOH.

Strong uncharged Lewis acids suitable as activating compounds (C) also include the reaction products of the reaction of a boronic acid with two equivalents of an aluminum trialkyl or the reaction products of the reaction of an aluminum trialkyl with two equivalents of an acidic fluorinated, in particular perfluorinated, carbon compound such as pentafluorophenol or bis(pentafluorophenyl)borinic acid.

Suitable ionic compounds having Lewis-acid cations include salt-like compounds of the cation of the general formula (XIII) [((M^(3D))^(a+))Q₁Q₂ . . . Q_(z)]^(d+)  (XIII) where

-   M^(3D) is an element of groups 1 to 16 of the Periodic Table of the     Elements, -   Q₁ to Q_(z) are simply negatively charged radicals such as     C₁-C₂₈-alkyl, C₆-C₁₅-aryl, alkylaryl, arylalkyl, haloalkyl, haloaryl     each having from 6 to 20 carbon atoms in the aryl part and from 1 to     28 carbon atoms in the alkyl part, C₃-C₁₀-cycloalkyl which may bear     C₁-C₁₀-alkyl groups as substituents, halogen, C₁-C₂₈-alkoxy,     C₆-C₁₅-aryloxy, silyl or mercaptyl groups, -   a is an integer from 1 to 6 and -   z is an integer from 0 to 5, -   d corresponds to the difference a−z, but d is greater than or equal     to 1.

Particularly useful cations are carbonium cations, oxonium cations and sulfonium cations and also cationic transition metal complexes. Particular mention may be made of the triphenylmethyl cation, the silver cation and the 1,1′-dimethylferrocenyl cation. They preferably have noncoordinating counterions, in particular boron compounds as are also mentioned in WO 91/09882, preferably tetrakis(pentafluorophenyl)borate.

Salts having noncoordinating anions can also be prepared by combining a boron or aluminum compound, e.g. an aluminum alkyl, with a second compound which can react to link two or more boron or aluminum atoms, e.g. water, and a third compound which forms with the boron or aluminium compound an ionizing ionic compound, e.g. triphenylchloromethane, or optionally a base, preferably an organic nitrogen-containing base, for example an amine, an aniline derivative or a nitrogen heterocycle. In addition, a fourth compound which likewise reacts with the boron or aluminum compound, e.g. pentafluorophenol, can be added.

Ionic compounds containing Brönsted acids as cations preferably likewise have noncoordinating counterions. As Brönsted acid, particular preference is given to protonated amine or aniline derivatives. Preferred cations are N,N-dimethylanilinium, N,N-dimethylcyclohexylammonium and N,N-dimethylbenzylammonium and also derivatives of the latter two.

Compounds containing anionic boron heterocycles as are described in WO 9736937 are also suitable as component (C), in particular dimethylanilinium boratabenzenes or trityl boratabenzenes.

Preferred ionic compounds C) contain borates which bear at least two perfluorinated aryl radicals. Particular preference is given to N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate and in particular N,N-dimethylcyclohexylammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylbenzylammonium tetrakis(pentafluorophenyl)borate or trityl tetrakispentafluorophenylborate.

It is also possible for two or more borate anions to be joined to one another, as in the dianion [(C₆F₅)₂B—C₆F₄—B(C₆F₅)₂]²⁻, or the borate anion can be bound via a bridge to a suitable functional group on the support surface.

Further suitable activating compounds (C) are listed in WO 00/31090.

The amount of strong, uncharged Lewis acids, ionic compounds having Lewis-acid cations or ionic compounds containing Brönsted acids as cations is preferably from 0.1 to 20 equivalents, more preferably from 1 to 10 equivalents and particularly preferably from 1 to 2 equivalents, based on the transition metal complex (A) or the iron complex (B).

Suitable activating compounds (C) also include boron-aluminum compounds such as di[bis(pentafluorophenylboroxy)]methylalane. Examples of such boron-aluminum compounds are those disclosed in WO 99/06414.

It is also possible to use mixtures of all the abovementioned activating compounds (C). Preferred mixtures comprise aluminoxanes, in particular methylaluminoxane, and an ionic compound, in particular one containing the tetrakis(pentafluorophenyl)borate anion, and/or a strong uncharged Lewis acid, in particular tris(pentafluorophenyl)borane or a boroxin.

Both the transition metal complex (A) or the iron complex (B) and the activating compounds (C) are preferably used in a solvent, preferably an aromatic hydrocarbon having from 6 to 20 carbon atoms, in particular xylenes, toluene, pentane, hexane, heptane or a mixture thereof.

A further possibility is to use an activating compound (C) which can simultaneously be employed as support (D). Such systems are obtained, for example, from an inorganic oxide treated with zirconium alkoxide and subsequent chlorination, e.g. by means of carbon tetrachloride. The preparation of such systems is described, for example, in WO 01/41920.

Combinations of the preferred embodiments of (C) with the preferred embodiments of (A) and/or (B) are particularly preferred.

As joint activator (C) for the catalyst component (A) and (B), preference is given to using an aluminoxane. Preference is also given to the combination of salt-like compounds of the cation of the general formula (XIII), in particular N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethylcyclohexylammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylbenzylammonium tetrakis(pentafluorophenyl)borate or trityl tetrakispentafluorophenylborate, as activator (C) for hafnocenes (A2), in particular in combination with an aluminoxane as activator (C) for the iron complex (B).

Further particularly useful joint activators (C) are the reaction products of aluminum compounds of the formula (XII) with perfluorinated alcohols and phenols.

To enable the transition metal complex (A) and the iron complex (B) to be used in polymerization processes in the gas phase or in suspension, it is often advantageous to use the complexes in the form of a solid, i.e. for them to be applied to a solid support (D). Furthermore, the supported complexes have a high productivity. The transition metal complexes (A) and/or the iron complex (B) can therefore also optionally be immobilized on an organic or inorganic support (D) and be used in supported form in the polymerization. This enables, for example, deposits in the reactor to be avoided and the polymer morphology to be controlled. As support materials, preference is given to using silica gel, magnesium chloride, aluminum oxide, mesoporous materials, aluminosilicates, hydrotalcites and organic polymers such as polyethylene, polypropylene, polystyrene, polytetrafluoroethylene or polymers bearing polar functional groups, for example copolymers of ethene and acrylic esters, acrolein or vinyl acetate.

Particular preference is given to a catalyst system comprising at least one transition metal complex (A), at least one iron complex (B), at least one activating compound (C) and at least one support component (D).

The preferred catalyst composition according to the invention comprises one or more support components. It is possible for both the transition metal component (A) and the iron complex (B) to be supported, or only one of the two components can be supported. In a preferred embodiment, both the components (A) and (B) are supported. The two components (A) and (B) can in this case be applied to different supports or together on a joint support. The components (A) and (B) are preferably applied to a joint support in order to ensure a relatively close spatial proximity of the various catalyst centers and thus to ensure good mixing of the different polymers formed.

To prepare the catalyst systems of the invention, preference is given to immobilizing one of the components (A) and one of the components (B) and/or activator (C) or the support (D) by physisorption or else by means of a chemical reaction, i.e. covalent binding of the components, with reactive groups on the support surface.

The order in which support component D), transition metal complex (A), iron complex (B) and the activating compounds (C) are combined is in principle immaterial. After the individual process steps, the various intermediates can be washed with suitable inert solvents such as aliphatic or aromatic hydrocarbons.

Transition metal complex (A), iron complex (B) and the activating compound (C) can be immobilized independently of one another, e.g. in succession or simultaneously. Thus, the support component (D) can firstly be brought into contact with the activating compound or compounds (C) or the support component (D) can firstly be brought into contact with the transition metal complex (A) and/or the iron complex (B). Preactivation of the transition metal complex A) by means of one or more activating compounds (C) prior to mixing with the support (D) is also possible. The iron component can, for example, be reacted simultaneously with the transition metal complex with the activating compound (C), or can be preactivated separately by means of the latter. The preactivated iron complex (B) can be applied to the support before or after the preactivated transition metal complex (A). In one possible embodiment, the transition metal complex (A) and/or the iron complex (B) can also be prepared in the presence of the support material. A further method of immobilization is prepolymerization of the catalyst system with or without prior application to a support.

The immobilization is generally carried out in an inert solvent which can be removed by filtration or evaporation after the immobilization. After the individual process steps, the solid can be washed with suitably inert solvents such as aliphatic or aromatic hydrocarbons and dried. However, the use of the still moist, supported catalyst is also possible.

In a preferred method of preparing the supported catalyst system, at least one iron complex (B) is brought into contact with an activated compound (C) and subsequently mixed with the dehydrated or passivated support material (D). The transition metal complex (A) is likewise brought into contact with at least one activating compound (C) in a suitable solvent, preferably giving a soluble reaction product, an adduct or a mixture. The preparation obtained in this way is then mixed with the immobilized iron complex, which is used directly or after the solvent has been separated off, and the solvent is completely or partly removed. The resulting supported catalyst system is preferably dried to ensure that all or most of the solvent is removed from the pores of the support material. The supported catalyst is preferably obtained as a free-flowing powder. Examples of the industrial implementation of the above process are described in WO 96/00243, WO 98/40419 or WO 00/05277. A further preferred embodiment comprises firstly producing the activating compound (C) on the support component (D) and subsequently bringing this supported compound into contact with the transition metal complex (A) and the iron complex (B).

As support component (D), preference is given to using finely divided supports which can be any organic or inorganic solid. In particular, the support component (D) can be a porous support such as talc, a sheet silicate such as montmorillonite, mica or an inorganic oxide or a finely divided polymer powder (e.g. polyolefin or a polymer having polar functional groups).

The support materials used preferably have a specific surface area in the range from 10 to 1000 m²/g, a pore volume in the range from 0.1 to 5 ml/g and a mean particle size of from 1 to 500 μm. Preference is given to supports having a specific surface area in the range from 50 to 700 m²/g, a pore volume in the range from 0.4 to 3.5 ml/g and a mean particle size in the range from 5 to 350 μm. Particular preference is given to supports having a specific surface area in the range from 200 to 550 m²/g, a pore volume in the range from 0.5 to 3.0 ml/g and a mean particle size of from 10 to 150 μm.

The transition metal complex (A) is preferably applied in such an amount that the concentration of the transition metal from the transition metal complex (A) in the finished catalyst system is from 1 to 200 μmol, preferably from 5 to 100 μmol and particularly preferably from 10 to 70 μmol, per g of support (D). The iron complex (B) is preferably applied in such an amount that the concentration of iron from the iron complex (B) in the finished catalyst system is from 1 to 200 μmol, preferably from 5 to 100 μmol and particularly preferably from 10 to 70 μmol, per g of support (D).

The inorganic support can be subjected to a thermal treatment, e.g. to remove adsorbed water. Such a drying treatment is generally carried out at temperatures in the range from 50 to 1000° C., preferably from 100 to 600° C., with drying at from 100 to 200° C. preferably being carried out under reduced pressure and/or under a blanket of inert gas (e.g. nitrogen), or the inorganic support can be calcined at temperatures of from 200 to 1000° C. to produce the desired structure of the solid and/or set the desired OH concentration on the surface. The support can also be treated chemically using customary dessicants such as metal alkyls preferably aluminum alkyls, chlorosilanes or SiCl₄, or else methylaluminoxane. Appropriate treatment methods are described, for example, in WO 00/31090.

The inorganic support material can also be chemically modified. For example, treatment of silica gel with NH₄SiF6 or other fluorinating agents leads to fluorination of the silica gel surface, or treatment of silica gels with silanes containing nitrogen-, fluorine- or sulfur-containing groups leads to correspondingly modified silica gel surfaces.

Organic support materials such as finely divided polyolefin powders (e.g. polyethylene, polypropylene or polystyrene) can also be used and are preferably likewise freed of adhering moisture, solvent residues or other impurities by appropriate purification and drying operations before use. It is also possible to use functionalized polymer supports, e.g. ones based on polystyrene, polyethylene, polypropylene or polybutylene, via whose functional groups, for example ammonium or hydroxy groups, at least one of the catalyst components can be immobilized. It is also possible to use polymer blends.

Inorganic oxides suitable as support component (D) may be found among the oxides of elements of groups 2, 3, 4, 5, 13, 14, 15 and 16 of the Periodic Table of the Elements. Examples of oxides preferred as supports include silicon dioxide, aluminum oxide and mixed oxides of the elements calcium, aluminum, silicon, magnesium or titanium and also corresponding oxide mixtures. Other inorganic oxides which can be used alone or in combination with the abovementioned preferred oxidic supports are, for example, MgO, CaO, AlPO₄, ZrO₂, TiO₂, B₂O₃ or mixtures thereof.

Further preferred inorganic support materials are inorganic halides such as MgCl₂ or carbonates such as Na₂CO₃, K₂CO₃, CaCO₃, MgCO₃, sulfates such as Na₂SO₄, Al₂(SO₄)₃, BaSO₄, nitrates such as KNO₃, Mg(NO₃)₂ or Al(NO₃)₃.

As solid support materials (D) for catalysts for olefin polymerization, preference is given to using silica gels since particles whose size and structure make them suitable as supports for olefin polymerization can be produced from this material. Spray-dried silica gels, which are spherical agglomerates of relatively small granular particles, i.e. primary particles, have been found to be particularly useful. The silica gels can be dried and/or calcined before use.

Further preferred supports (D) are hydrotalcites and calcined hydrotalcites. In mineralogy, hydrotalcite is a natural mineral having the ideal formula Mg₆Al₂(OH)₁₆CO₃.4H₂O whose structure is derived from that of brucite Mg(OH)₂. Brucite crystallizes in a sheet structure with the metal ions in octahederal holes between two layers of close-packed hydroxyl ions, with only every second layer of the octahederal holes being occupied. In hydrotalcite, some magnesium ions are replaced by aluminum ions, as a result of which the packet of layers gains a positive charge. This is balanced by the anions which are located together with water of crystallization in the layers in-between.

Such sheet structures are found not only in magnesium-aluminum-hydroxides, but generally in mixed metal hydroxides of the general formula M(II)_(2x) ²⁺M(III)₂ ³⁺(OH)_(4x+4).A_(2/n) ^(n−).zH₂O which have a sheet structure and in which M(II) is a divalent metal such as Mg, Zn, Cu, Ni, Co, Mn, Ca and/or Fe and M(III) is a trivalent metal such as Al, Fe, Co, Mn, La, Ce and/or Cr, x is a number from 0.5 to 10 in steps of 0.5, A is an interstitial anion and n is the charge on the interstitial anion which can be from 1 to 8, usually from 1 to 4, and z is an integer from 1 to 6, in particular from 2 to 4. Possible interstitial anions are organic anions such as alkoxide anions, alkyl ether sulfates, aryl ether sulfates or glycol ether sulfates, inorganic anions such as, in particular, carbonate, hydrogen carbonate, nitrate, chloride, sulfate or B(OH)₄ ⁻ or polyoxometal anions such as Mo₇O₂₄ ⁶⁻ or V₁₀O₂₈ ⁶⁻. However, a mixture of a plurality of such anions is also possible.

Accordingly, all such mixed metal hydroxides having a sheet structure should be regarded as hydrotalcites for the purposes of the present invention.

Calcined hydrotalcites can be prepared from hydrotalcites by calcination, i.e. heating, by means of which, inter alia, the desired hydroxide group content can be set. In addition, the crystal structure also changes. The preparation of the calcined hydrotalcites used according to the invention is usually carried out at temperatures above 180° C. Preference is given to calcination for a period of from 3 to 24 hours at temperatures of from 250° C. to 1000° C., in particular from 400° C. to 700° C. It is possible for air or inert gas to be passed over the solid or for a vacuum to be applied at the same time.

On heating, the natural or synthetic hydrotalcites firstly give off water, i.e. drying occurs. On further heating, the actual calcination, the metal hydroxides are converted into the metal oxides by elimination of hydroxyl groups and interstitial anions; OH groups or interstitial anions such as carbonate can also still be present in the calcined hydrotalcites. A measure of this is the loss on ignition. This is the weight loss experienced by a sample which is heated in two steps firstly for 30 minutes at 200° C. in a drying oven and then for 1 hour at 950° C. in a muffle furnace.

The calcined hydrotalcites used as component (D) are thus mixed oxides of the divalent and trivalent metals M(II) and M(III), with the molar ratio of M(II) to M(III) generally being in the range from 0.5 to 10, preferably from 0.75 to 8 and in particular from 1 to 4. Furthermore, normal amounts of impurities, for example Si, Fe, Na, Ca or Ti and also chlorides and sulfates, can also be present.

Preferred calcined hydrotalcites (D) are mixed oxides in which M(II) is magnesium and M(III) is aluminum. Such aluminum-magnesium mixed oxides are obtainable from Condea Chemie GmbH (now Sasol Chemie), Hamburg under the trade name Puralox Mg.

Preference is also given to calcined hydrotalcites in which the structural transformation is complete or virtually complete. Calcination, i.e. transformation of the structure, can be confirmed, for example, by means of X-ray diffraction patterns.

The hydrotalcites, calcined hydrotalcites or silica gels used are generally used as finely divided powders having a mean particle diameter D50 of from 5 to 200 μm, preferably from 10 to 150 μm, particularly preferably from 15 to 100 μm and in particular from 20 to 70 μm, and usually have pore volumes of from 0.1 to 10 cm³/g, preferably from 0.2 to 5 cm³/g, and specific surface areas of from 30 to 1000 m²/g, preferably from 50 to 800 m²/g and in particular from 100 to 600 m²/g. The transition metal complex (A) is preferably applied in such an amount that the concentration of the transition metal from the transition metal complex (A) in the finished catalyst system is from 1 to 100 μmol, preferably from 5 to 80 μmol and particularly preferably from 10 to 60 μmol, per g of support (D).

The catalyst system may further comprise, as additional component (E), a metal compound of the general formula (XX), M^(G)(R^(1C))_(r) _(G) (R^(2G))_(r) _(G) (R^(3G))_(t) _(G)   (XX) where

-   M^(G) is Li, Na, K, Be, Mg, Ca, Sr, Ba, boron, aluminum, gallium,     indium, thallium, zinc, in particular Li, Na, K, Mg, boron, aluminum     or Zn, -   R^(1G) is hydrogen, C₁-C₁₀-alkyl, C₆-C₁₅-aryl, alkylaryl or     arylalkyl each having from 1 to 10 carbon atoms in the alkyl part     and from 6 to 20 carbon atoms in the aryl part, -   R^(2G) and R^(3G) are each hydrogen, halogen, C₁-C₁₀-alkyl,     C₈-C₁₅-aryl, alkylaryl, arylalkyl or alkoxy each having from 1 to 20     carbon atoms in the alkyl part and from 6 to 20 carbon atoms in the     aryl part, or alkoxy together with C₁-C₁₀-alkyl or C₆-C₁₅-aryl, -   r^(G) is an integer from 1 to 3 and -   s^(G) and t^(G) are integers from 0 to 2, with the sum     r^(G)+s^(G)+t^(G) corresponding to the valence of M^(G),     where the component (E) is usually not identical to the component     (C). It is also possible to use mixtures of various metal compounds     of the formula (XX).

Among the metal compounds of the general formula (XX), preference is given to those in which

M^(G) is lithium, magnesium, boron or aluminum and

R^(1G) is C₁-C₂₀-alkyl.

Particularly preferred metal compounds of the formula (XX) are methyllithium, ethyllithium, n-butyllithium, methylmagnesium chloride, methylmagnesium bromide, ethylmagnesium chloride, ethylmagnesium bromide, butylmagnesium chloride, dimethylmagnesium, diethylmagnesium, dibutylmagnesium, n-butyl-n-octylmagnesium, n-butyl-n-heptylmagnesium, in particular n-butyl-n-octylmagnesium, tri-n-hexylaluminum, triisobutylaluminum, tri-n-butylaluminum, triethylaluminum, dimethylaluminum chloride, dimethylaluminum fluoride, methylaluminum dichloride, methylaluminum sesquichloride, diethylaluminum chloride and trimethylaluminum and mixtures thereof. The partial hydrolysis products of aluminum alkyls with alcohols can also be used.

When a metal compound (E) is used, it is preferably present in the catalyst system in such an amount that the molar ratio of M^(G) from formula (XX) to the sum of the transition metals from the transition metal complex (A) and the iron complex (B) is from 3000:1 to 0.1:1, preferably from 800:1 to 0.2:1 and particularly preferably from 100:1 to 1:1.

In general, the metal compound (E) of the general formula (XX) is used as constituent of a catalyst system for the polymerization or copolymerization of olefins. Here, the metal compound (E) can, for example, be used for preparing a catalyst solid comprising the support (D) and/or be added during or shortly before the polymerization. The metal compounds (E) used can be identical or different. It is also possible, particularly when the catalyst solid contains no activating component (C), for the catalyst system to further comprise, in addition to the catalyst solid, one or more activating compounds (C) which are identical to or different from any compounds (E) present in the catalyst solid.

The component E) can likewise be reacted in any order with the components (A), (B) and optionally (C) and (D). The component (A) can, for example, be brought into contact with the component(s) (C) and/or (D) either before or after being brought into contact with the olefins to be polymerized. Preactivation by means of one or more components (C) prior to mixing with the olefin and further addition of the same or another component (C) and/or (D) after this mixture has been brought into contact with the olefin is also possible. Preactivation is generally carried out at temperatures of 10-100° C., preferably 20-80° C.

In another preferred embodiment, a catalyst solid is prepared from the components (A), (B), (C) and (D) as described above and this is brought into contact with the component (E) during, at the commencement of or shortly before the polymerization.

Preference is given to firstly bringing (E) into contact with the α-olefin to be polymerized and subsequently adding the catalyst solid comprising the components (A), (B), (C) and (D) as described above.

In a further, preferred embodiment, the support (D) is firstly brought into contact with the component (E), and the components (A) and (B) and any further activator (C) are then dealt with as described above.

It is also possible for the catalyst system firstly to be prepolymerized with α-olefins, preferably linear C₂-C₁₀-1-alkenes and in particular ethylene or propylene, and the resulting prepolymerized catalyst solid then to be used in the actual polymerization. The mass ratio of catalyst solid used in the prepolymerization to a monomer polymerized onto it is usually in the range from 1:0.1 to 1:1000, preferably from 1:1 to 1:200.

Furthermore, a small amount of an olefin, preferably an α-olefin, for example vinylcyclohexane, styrene or phenyldimethylvinylsilane, as modifying component, an antistatic or a suitable inert compound such as a wax or oil can be added as additive during or after the preparation of the catalyst system. The molar ratio of additives to the sum of transition metal compound (A) and iron complex (B) is usually from 1:1000 to 1000:1, preferably from 1:5 to 20:1.

The catalyst composition or catalyst system of the invention is suitable for preparing the polyethylene of the invention, which has advantageous use and processing properties.

To prepare the polyethylene of the invention, the ethylene is polymerized as described above with α-olefins having from 3 to 12 carbon atoms.

In the copolymerization process of the invention, ethylene is polymerized with α-olefins having from 3 to 12 carbon atoms. Preferred α-olefins are linear or branched C₂-C₁₂-1-alkenes, in particular linear C₂-C₁₀-1-alkenes such as ethene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene or branched C₂-C₁₀-1-alkenes such as 4-methyl-1-pentene. Particularly preferred α-olefins are C₄-C₁₂-1-alkenes, in particular linear C₆-C₁₀-1-alkenes. It is also possible to polymerize mixtures of various α-olefins. Preference is given to polymerizing at least one α-olefin selected from the group consisting of ethene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-decene. Monomer mixtures containing at least 50 mol % of ethene are preferably used.

The process of the invention for polymerizing ethylene with α-olefins can be carried out using all industrially known polymerization methods at temperatures in the range from −60 to 350° C., preferably from 0 to 200° C. and particularly preferably from 25 to 150° C., and under pressures of from 0.5 to 4000 bar, preferably from 1 to 100 bar and particularly preferably from 3 to 40 bar. The polymerization can be carried out in a known manner in bulk, in suspension, in the gas phase or in a supercritical medium in the customary reactors used for the polymerization of olefins. It can be carried out batchwise or preferably continuously in one or more stages. High-pressure polymerization processes in tube reactors or autoclaves, solution processes, suspension processes, stirred gas-phase processes and gas-phase fluidized-bed processes are all possible.

The polymerizations are usually carried out at temperatures in the range from −60 to 350° C., preferably in the range from 20 to 300° C., and under pressures of from 0.5 to 4000 bar. The mean residence times are usually from 0.5 to 5 hours, preferably from 0.5 to 3 hours. The advantageous pressure and temperature ranges for carrying out the polymerizations usually depend on the polymerization method. In the case of high-pressure polymerization processes, which are customarily carried out at pressures of from 1000 to 4000 bar, in particular from 2000 to 3500 bar, high polymerization temperatures are generally also set. Advantageous temperature ranges for these high-pressure polymerization processes are from 200 to 320° C., in particular from 220 to 290° C. In the case of low-pressure polymerization processes, it is usual to set a temperature which is at least a few degrees below the softening temperature of the polymer. In particular, temperatures of from 50 to 180° C., preferably from 70 to 120° C., are set in these polymerization processes. In the case of suspension polymerizations, the polymerization is usually carried out in a suspension medium, preferably an inert hydrocarbon such as isobutane or mixtures of hydrocarbons or else in the monomers themselves. The polymerization temperatures are generally in the range from −20 to 115° C., and the pressure is generally in the range from 1 to 100 bar. The solids content of the suspension is generally in the range from 10 to 80%. The polymerization can be carried out either batchwise, e.g. in stirring autoclaves, or continuously, e.g. in tube reactors, preferably in loop reactors. Particular preference is given to employing the Phillips PF process as described in U.S. Pat. No. 3,242,150 and U.S. Pat. No. 3,248,179. The gas-phase polymerization is generally carried out in the range from 30 to 125° C. at pressures of from 1 to 50 bar.

Among the abovementioned polymerization processes, particular preference is given to gas-phase polymerization, in particular in gas-phase fluidized-bed reactors, solution polymerization and suspension polymerization, in particular in loop reactors and stirred tank reactors. The gas-phase polymerization can also be carried out in the condensed or supercondensed mode, in which part of the circulating gas is cooled to below the dew point and is recirculated as a two-phase mixture to the reactor. Furthermore, it is possible to use a multizone reactor in which the two polymerization zones are linked to one another and the polymer is passed alternately through these two zones a number of times. The two zones can also have different polymerization conditions. Such a reactor is described, for example, in WO 97/04015. The different or identical polymerization processes can also, if desired, be connected in series so as to form a polymerization cascade, for example as in the Hostalen® process. A parallel reactor arrangement using two or more identical or different processes is also possible. Furthermore, molar mass regulators, for example hydrogen, or customary additives such as antistatics can also be used in the polymerizations.

The polymerization is preferably carried out in a single reactor, in particular in a gas-phase reactor. The polymerization of ethylene with α-olefins having from 3 to 12 carbon atoms gives the polyethylene of the invention when the catalyst of the invention is used. The polyethylene powder obtained directly from the reactor displays a very high homogeneity, so that, unlike the case of cascade processes, subsequent extrusion is not necessary in order to obtain a homogeneous product.

The production of polymer blends by intimate mixing of individual components, for example by melt extrusion in an extruder or kneader (cf., for example, “Polymer Blends” in Ullmann's Encyclopedia of Industrial Chemistry, 6^(th) Edition, 1998, Electronic Release), is often accompanied by particular difficulties. The melt viscosities of the high and low molecular weight components of a bimodal polyethylene blend are extremely different. While the low molecular weight component is quite fluid at the customary temperatures of about 190-210° C. used for producing the blends, the high molecular weight component is only softened (“lentil soup”). Homogeneous mixing of the two components is therefore for very difficult. In addition, it is known that the high molecular weight component can easily be damaged as a result of thermal stress and by shear forces in the extruder, so that the properties of the blend are adversely affected. The mixing quality of such polyethylene blends is therefore often unsatisfactory.

The mixing quality of the polyethylene powder obtained directly from the reactor can be tested by assessing thin slices (“microtome sections”) of a sample under an optical microscope. Inhomogenities show up in the form of specks or “white spots”. The specs or “white spots” are predominantly high molecular weight, high-viscosity particles in a low-viscosity matrix (cf., for example, U. Burkhardt et al. in “Aufbereiten von Polymeren mit neuartigen Eigenschaften”, VDI-Verlag, Düsseldorf 1995, p. 71). Such inclusions can reach a size of up to 300 μm, cause stress cracks and result in brittle failure of components. The better the mixing quality of a polymer, the fewer and smaller are these inclusions observed. The mixing quality of a polymer is determined quantitatively in accordance with ISO 13949. According to the measurement method, a microtome section is prepared from a sample of the polymer, the number and size of these inclusions are counted and a grade is determined for the mixing quality of the polymer according to a set assessment scheme. The mixing quality in the polyethylene directly obtained from the reactor, the polymer powder without extrusion is preferably less than 3.

The preparation of the polyethylene of the invention in the reactor reduces the energy consumption, requires no subsequent blending processes and makes simple control of the molecular weight distributions and the molecular weight fractions of the various polymers possible. In addition, good mixing of the polyethylene is achieved.

The following examples illustrate the invention without restricting the scope of the invention.

The measured values described were determined in the following way:

NMR samples were placed in tubes under inert gas and, if appropriate, melted. The solvent signals served as internal standard in the ¹H- and ^(13C)-NMR spectra and their chemical shift was converted into the values relative to TMS.

The vinyl group content is determined by means of IR in accordance with ASTM D 6248-98. The branches/1000 carbon atoms are determined by means of ¹³C-NMR, as described by James. C. Randall, JMS-REV. Macromol. Chem. Phys., C29 (2&3), 201-317 (1989), and are based on the total content of CH₃ groups/1000 carbon atoms including end groups. The side chains larger than CH₃ and especially ethyl, butyl and hexyl side chain branches/1000 carbon atoms excluding end groups are likewise determined in this way.

The degree of branching in the individual polymer fractions is determined by the method of Holtrup (W. Holtrup, Makromol. Chem. 178, 2335 (1977)) coupled with ¹³C-NMR. as described by James. C. Randall, JMS-REV. Macromol. Chem. Phys., C29 (2&3), 201-317 (1989)

The density [g/cm³] was determined in accordance with ISO 1183.

The determination of the molar mass distributions and the means Mn, Mw, and Mw/Mn derived therefrom was carried out by means of high-temperature gel permeation chromatography on a WATERS 150 C using a method based on DIN 55672 and the following columns connected in series: 3× SHODEX AT 806 MS, 1× SHODEX UT 807 and 1× SHODEX AT-G under the following conditions: solvent: 1,2,4-trichlorobenzene (stabilized with 0.025% by weight of 2,6-di-tert-butyl-4-methylphenol), flow: 1 ml/min, 500 μl injection volume, temperature: 135° C., calibration using PE Standards. Evaluation was carried out using WIN-GPC.

For the purposes of the present invention, the expression “HLMI” refers, as is generally known, to the “high load melt flow, rate” and is always determined at 190° C. under a load of 21.6 kg (190° C./21.6 kg) in accordance with ISO 1133.

The haze, as determined according to ASTM D 1003-00 on a BYK Gardener Haze Guard Plus Device on at least 5 pieces of film 10×10 cm with a thickness of 1 mm.

The impact resistance was determined according to the instrument falling weight impact test according to ISO 6603 at −20° C.

The stress crack resistance (full notch creep test (FNCT)) was determined according to ISO DIS2 16770 at a pressure of 3.5 Mbar at 80° C. in a 2% by weight solution of Akropal N(N=10) in water.

The spiral flow test was measured on a Demag ET100-310 with a closing pressure of 100 t and a 3 mm die and with a stock temperature of 250° C., an injection pressure of 1000 bar, a screw speed of 90 mm/s, a mold temperature of 30° C. and wall thickness 2 mm.

Abbreviations in the table below:

-   Cat. Catalyst -   T(poly) Polymerisation temperature -   M_(w) Weight average molar mass -   M_(n) Number average molar mass -   Density Polymer density -   Vinyl/1000C refers to the amount of Vinyl groups per 1000 carbon     atoms -   b/1000C refers to branches/1000 carbon atoms, which is the amount of     CH₃/1000 carbon atoms including end groups -   br in 15% PE hmw refers to the 15% by weight of the polyethylene     having the highest molar masses with a degree of branches of side     chains larger than CH₃/1000 carbon atoms excluding end groups -   Prod. Productivity of the catalyst in g of polymer obtained per g of     catalyst used per hour -   Impact Impact resistance as determined according to the instrument     falling weight impact test according to ISO 6603 at −20° C.     Preparation of the Individual Components

Bis(n-butylcyclopentadienyl)hafnium dichloride is commercially available from Crompton.

2,6-Bis[i-(2,4-dichloro-6-methylphenylimino)ethyl]pyridine iron(II) dichloride was prepared according to the method of Qian et al., Organometallics 2003, 22, 4312-4321. Here, 65.6 g of 2,6-diacetylpyridine (0.4 mol), 170 g of 2,4-dichloro-6-methylaniline (0.483 mol), 32 g of silica gel type 135 and 160 g of molecular sieves (4 Å) were stirred in 1500 ml of toluene at 80° C. for 5 hours and a further 32 g of silica gel type 135 and 160 g of molecular sieves (4 Å) were subsequently added. The mixture was stirred at 80° C. for a further 8 hours, the insoluble solid was filtered off and washed twice with toluene. The solvent was distilled off from the filtrate obtained in this way, the residue was admixed with 200 ml of methanol and subsequently stirred at 55° C. for 1 hour. The suspension formed in this way was filtered and the solid obtained washed with methanol and freed of the solvent. This gave 95 g of 2,6-Bis[i-(2,4-dichloro-6-methylphenylimino)ethyl]-pyridine in 47% yield. The reaction with iron(II) chloride was carried out as described by Qian et al., Organometallics 2003, 22, 4312-4321.

Preparation of the Mixed Catalyst Systems

EXAMPLE 1

a) Support Pretreatment

XPO-2107, a spray-dried silica gel from Grace, was baked at 600° C. for 6 hours.

B) Preparation of the Mixed Catalyst Systems

A mixture of 1.43 g (2.37 mmol) of 2,6-Bis[1-(2,4-dichloro-6-methylphenylimino)ethyl]pyridine iron(II) dichloride, 9.98 g of bis(n-butylcyclopentadienyl)hafnium dichloride and 443 ml of MAO (4.75 M in toluene, 2.1 mol) was stirred at room temperature for 1 h and subsequently added while stirring to 338 g of the pretreated support material a) in 500 ml of toluene. The resulting solid gave 778.4 g of catalyst which still contained 23.9% by weight of solvent (based on the total weight and calculated on the basis of complete application of all components to the support).

Polymerization of the Catalysts

The polymerization was carried out in a fluidized-bed reactor having a diameter of 0.5 m and an overall pressure of 20 bar. The polymerization temperature was 95° C. using the catalyst of example 1, which was fed at a rate of 38.97 g per h to the reactor. Ethylene was fed to the reactor at a rate of 40.7 kg per h, 1-hexene at a rate of 410 g per h and hydrogen at 2.1 l per h. Also 4.62 kg propane per h, 0.33 kg nitrogen per h and 0.5 g triisobutylaluminium per h were fed to the reactor. Polymer was discharged at 30.1 kg/h. The properties of the polymers obtained are summarized in Table 1.

COMPARATIVE EXAMPLE 1

A Ziegler catalyst was prepared as described in EP-A-739937 and polymerization was carried out in a suspension cascade using ethylene/hydrogen in the 1 st reactor and ethylene/1-butene with 0.8% by weight of 1-butene in the 2nd reactor. The product data are shown in Table 1. TABLE 1 Cat. Prod. HLMI Mw density Vinyl/ branches/ br in 15% from Ex. [g/g] [g/10 min] [g/mol] M_(w)/M_(n) [g/cm³] 1000C 1000C PE hmw 1 3792 109 99000 7.9 0.953 1.3 3.9 5 C1 75 116300 10 0.953 0.12 1 0.5

The polymers were each formed into small plates of 1 mm thickness on an Engel injection molding machine. The extrusion temperature was 225° C., the screw speed 116 turns per min and an injection speed of 50 mm/s. The holding time was 20 s, the holding pressure 687 bar. TABLE 2 Properties of the polyethylenes Example 1 V1 Spiral length, 250° C. [cm] 47.6 36 FNCT (3.5 MPa, 80°) [h] 7.4 1.3 Haze [%] 90.80 94.20 Impact (−20° C.) [J] 12.42 11.21 

1-9. (canceled)
 10. A polyethylene which comprises ethylene homopolymers, copolymers of ethylene with 1-alkenes or mixtures thereof, having a molar mass distribution width M_(w)/M_(n) of from 3 to 30, a density of from 0.945 to 0.965 g/cm³, a weight average molar mass M_(w) of from 50,000 g/mol to 200,000 g/mol, an HLMI of from 10 to 300 g/10 min and has from 0.1 to 15 branches/1000 carbon atoms, wherein the 1 to 15% by weight of the polyethylene having the highest molar masses have a degree of branching of more than 1 branch of side chains larger than CH₃/1000 carbon atoms, and the 5-50% by weight of the polyethylene having the lowest molar masses have a degree of branching of less than 10 branches/1000 carbon atoms.
 11. The polyethylene according to claim 10 comprising an at least bimodal short chain branching distribution.
 12. The polyethylene according to claim 10 wherein the degree of branching is from 0.2 to 8 branches/1000 carbon atoms.
 13. The polyethylene according to claim 10 which has been prepared in a single reactor.
 14. An injection molding comprising a polyethylene, the polyethylene comprising a polyethylene which comprises ethylene homopolymers, copolymers of ethylene with 1-alkenes or mixtures thereof, having a molar mass distribution width M_(w)/M_(n) of from 3 to 30, a density of from 0.945 to 0.965 g/cm³, a weight average molar mass M_(w) of from 50,000 g/mol to 200,000 g/mol, an HLMI of from 10 to 300 g/10 min and has from 0.1 to 15 branches/1000 carbon atoms, wherein the 1 to 15% by weight of the polyethylene having the highest molar masses have a degree of branching of more than 1 branch of side chains larger than CH₃/1000 carbon atoms, and the 5-50% by weight of the polyethylene having the lowest molar masses have a degree of branching of less than 10 branches/1000 carbon atoms.
 15. The injection molding according to claim 14, with a haze as determined according to ASTM D 1003-00 of less than 94%.
 16. The injection molding according to claim 14 with a stress cracking resistance (FNCT) as determined according to ISO DIS2 16770 at a pressure of 3.5 Mbar at 80° C. in a 2% by weight solution of Akropal N(N=10) in water, of at least 5 h.
 17. The injection molding according to claim 14, wherein the injection molding is a cap, closure, screw cap, screw closure, tube shoulder or engineering part.
 18. The injection molding according to claim 14 wherein the injection molding is a screw cap. 